DRTVWR-592: (WIP) (has debug) Add new functions for mixing PBR materials. Not yet used.
Cosmic Linden
parent
00d56e2607
commit
b163f72ecc
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@ -44,18 +44,99 @@
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* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*/
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#define TERRAIN_PBR_DETAIL_EMISSIVE 0
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in vec3 vary_vertex_normal;
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vec3 srgb_to_linear(vec3 c);
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// A relatively agressive threshold ensures that only one or two materials are used in most places
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// A relatively agressive threshold for terrain material mixing sampling
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// cutoff. This ensures that only one or two materials are used in most places,
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// making PBR terrain blending more performant. Should be greater than 0 to work.
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#define TERRAIN_RAMP_MIX_THRESHOLD 0.1
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// A small threshold for triplanar mapping sampling cutoff. This and
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// TERRAIN_TRIPLANAR_BLEND_FACTOR together ensures that only one or two samples
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// per texture are used in most places, making triplanar mapping more
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// performant. Should be greater than 0 to work.
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// There's also an artistic design choice in the use of these factors, and the
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// use of triplanar generally. Don't take these triplanar constants for granted.
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#define TERRAIN_TRIPLANAR_MIX_THRESHOLD 0.01
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#define MIX_X 1 << 3
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#define MIX_Y 1 << 2
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#define MIX_Z 1 << 1
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#define MIX_W 1 << 0
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#define SAMPLE_X 1 << 0
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#define SAMPLE_Y 1 << 1
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#define SAMPLE_Z 1 << 2
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#define MIX_X 1 << 3
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#define MIX_Y 1 << 4
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#define MIX_Z 1 << 5
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#define MIX_W 1 << 6
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struct PBRMix
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{
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vec4 col; // RGB color with alpha, linear space
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vec3 orm; // Occlusion, roughness, metallic
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vec3 vNt; // Unpacked normal texture sample, vector
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#if (TERRAIN_PBR_DETAIL >= TERRAIN_PBR_DETAIL_EMISSIVE)
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vec3 emissive; // RGB emissive color, linear space
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#endif
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};
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PBRMix init_pbr_mix()
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{
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PBRMix mix;
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mix.col = vec4(0);
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mix.orm = vec3(0);
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mix.vNt = vec3(0);
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#if (TERRAIN_PBR_DETAIL >= TERRAIN_PBR_DETAIL_EMISSIVE)
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mix.emissive = vec3(0);
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#endif
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return mix;
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}
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// Usage example, for two weights:
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// vec2 weights = ... // Weights must add up to 1
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// PBRMix mix = init_pbr_mix();
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// PBRMix mix1 = ...
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// mix = mix_pbr(mix, mix1, weights.x);
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// PBRMix mix2 = ...
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// mix = mix_pbr(mix, mix2, weights.y);
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PBRMix mix_pbr(PBRMix mix1, PBRMix mix2, float mix2_weight)
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{
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PBRMix mix;
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mix.col = mix1.col + (mix2.col * mix2_weight);
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mix.orm = mix1.orm + (mix2.orm * mix2_weight);
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mix.vNt = mix1.vNt + (mix2.vNt * mix2_weight);
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#if (TERRAIN_PBR_DETAIL >= TERRAIN_PBR_DETAIL_EMISSIVE)
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mix.emissive = mix1.emissive + (mix2.emissive * mix2_weight);
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#endif
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return mix;
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}
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PBRMix sample_pbr(
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vec2 uv
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, sampler2D tex_col
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, sampler2D tex_orm
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, sampler2D tex_vNt
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#if (TERRAIN_PBR_DETAIL >= TERRAIN_PBR_DETAIL_EMISSIVE)
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, sampler2D tex_emissive
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#endif
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)
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{
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PBRMix mix;
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mix.col = texture(tex_col, uv);
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mix.col.rgb = srgb_to_linear(mix.col.rgb);
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mix.orm = texture(tex_orm, uv).xyz;
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mix.vNt = texture(tex_vNt, uv).xyz*2.0-1.0;
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#if (TERRAIN_PBR_DETAIL >= TERRAIN_PBR_DETAIL_EMISSIVE)
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mix.emissive = srgb_to_linear(texture(tex_emissive, uv).xyz);
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#endif
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return mix;
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}
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struct TerrainTriplanar
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{
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vec3 weight;
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int type;
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};
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#if 0 // TODO: Remove debug
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#define TERRAIN_DEBUG 1
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@ -97,6 +178,24 @@ TerrainMix _t_mix(float alpha1, float alpha2, float alphaFinal)
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return tm;
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}
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TerrainTriplanar _t_triplanar()
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{
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float sharpness = TERRAIN_TRIPLANAR_BLEND_FACTOR;
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float threshold = TERRAIN_TRIPLANAR_MIX_THRESHOLD;
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vec3 weight_signed = pow(abs(vary_vertex_normal), vec3(sharpness));
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weight_signed /= (weight_signed.x + weight_signed.y + weight_signed.z);
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weight_signed -= vec3(threshold);
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TerrainTriplanar tw;
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// *NOTE: Make sure the threshold doesn't affect the materials
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tw.weight = max(vec3(0), weight_signed);
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tw.weight /= (tw.weight.x + tw.weight.y + tw.weight.z);
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ivec3 usage = ivec3(round(max(vec3(0), sign(weight_signed))));
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tw.type = ((usage.x) * SAMPLE_X) |
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((usage.y) * SAMPLE_Y) |
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((usage.z) * SAMPLE_Z);
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return tw;
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}
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float terrain_mix(vec4 samples, float alpha1, float alpha2, float alphaFinal)
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{
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TerrainMix tm = _t_mix(alpha1, alpha2, alphaFinal);
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@ -130,7 +229,6 @@ vec3 terrain_mix(TerrainMix tm, TerrainMixSample3 tms3)
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// Pre-transformed texture coordinates for each axial uv slice (Packing: xy, yz, (-x)z, unused)
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#define TerrainCoord vec4[2]
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#define TERRAIN_TRIPLANAR_MIX_THRESHOLD 0.01
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vec4 _t_texture(sampler2D tex, vec2 uv_unflipped, float sign_or_zero)
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{
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@ -143,31 +241,50 @@ vec4 _t_texture(sampler2D tex, vec2 uv_unflipped, float sign_or_zero)
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return texture(tex, uv);
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}
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#define SAMPLE_X 1 << 2
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#define SAMPLE_Y 1 << 1
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#define SAMPLE_Z 1 << 0
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struct TerrainWeight
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vec2 _t_uv(vec2 uv_unflipped, float sign_or_zero)
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{
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vec3 weight;
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int type;
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};
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// Handle case where sign is 0
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float sign = (2.0*sign_or_zero) + 1.0;
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sign /= abs(sign);
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// If the vertex normal is negative, flip the texture back
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// right-side up.
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vec2 uv = uv_unflipped * vec2(sign, 1);
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return uv;
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}
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TerrainWeight _t_weight(TerrainCoord terrain_coord)
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vec3 _t_normal_post_1(vec3 vNt0, float sign_or_zero)
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{
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float sharpness = TERRAIN_TRIPLANAR_BLEND_FACTOR;
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float threshold = TERRAIN_TRIPLANAR_MIX_THRESHOLD;
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vec3 weight_signed = pow(abs(vary_vertex_normal), vec3(sharpness));
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weight_signed /= (weight_signed.x + weight_signed.y + weight_signed.z);
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weight_signed -= vec3(threshold);
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TerrainWeight tw;
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// *NOTE: Make sure the threshold doesn't affect the materials
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tw.weight = max(vec3(0), weight_signed);
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tw.weight /= (tw.weight.x + tw.weight.y + tw.weight.z);
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ivec3 usage = ivec3(round(max(vec3(0), sign(weight_signed))));
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tw.type = ((usage.x) * SAMPLE_X) |
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((usage.y) * SAMPLE_Y) |
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((usage.z) * SAMPLE_Z);
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return tw;
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// Assume normal is unpacked
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vec3 vNt1 = vNt0;
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// Get sign
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float sign = sign_or_zero;
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// Handle case where sign is 0
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sign = (2.0*sign) + 1.0;
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sign /= abs(sign);
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// If the sign is negative, rotate normal by 180 degrees
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vNt1.xy = (min(0, sign) * vNt1.xy) + (min(0, -sign) * -vNt1.xy);
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return vNt1;
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}
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// Triplanar-specific normal texture fixes
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vec3 _t_normal_post_x(vec3 vNt0)
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{
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vec3 vNt_x = _t_normal_post_1(vNt0, sign(vary_vertex_normal.x));
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// *HACK: Transform normals according to orientation of the UVs
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vNt_x.xy = vec2(-vNt_x.y, vNt_x.x);
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return vNt_x;
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}
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vec3 _t_normal_post_y(vec3 vNt0)
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{
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vec3 vNt_y = _t_normal_post_1(vNt0, sign(vary_vertex_normal.y));
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// *HACK: Transform normals according to orientation of the UVs
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vNt_y.xy = -vNt_y.xy;
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return vNt_y;
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}
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vec3 _t_normal_post_z(vec3 vNt0)
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{
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vec3 vNt_z = _t_normal_post_1(vNt0, sign(vary_vertex_normal.z));
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return vNt_z;
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}
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struct TerrainSample
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@ -177,7 +294,7 @@ struct TerrainSample
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vec4 z;
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};
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TerrainSample _t_sample(sampler2D tex, TerrainCoord terrain_coord, TerrainWeight tw)
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TerrainSample _t_sample(sampler2D tex, TerrainCoord terrain_coord, TerrainTriplanar tw)
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{
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TerrainSample ts;
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@ -227,7 +344,7 @@ struct TerrainSampleNormal
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vec3 z;
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};
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TerrainSampleNormal _t_sample_n(sampler2D tex, TerrainCoord terrain_coord, TerrainWeight tw)
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TerrainSampleNormal _t_sample_n(sampler2D tex, TerrainCoord terrain_coord, TerrainTriplanar tw)
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{
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TerrainSample ts = _t_sample(tex, terrain_coord, tw);
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TerrainSampleNormal tsn;
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@ -250,7 +367,7 @@ TerrainSampleNormal _t_sample_n(sampler2D tex, TerrainCoord terrain_coord, Terra
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return tsn;
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}
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TerrainSample _t_sample_c(sampler2D tex, TerrainCoord terrain_coord, TerrainWeight tw)
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TerrainSample _t_sample_c(sampler2D tex, TerrainCoord terrain_coord, TerrainTriplanar tw)
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{
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TerrainSample ts = _t_sample(tex, terrain_coord, tw);
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ts.x.xyz = srgb_to_linear(ts.x.xyz);
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@ -262,7 +379,7 @@ TerrainSample _t_sample_c(sampler2D tex, TerrainCoord terrain_coord, TerrainWeig
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// Triplanar sampling of things that are neither colors nor normals (i.e. orm)
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vec4 terrain_texture(sampler2D tex, TerrainCoord terrain_coord)
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{
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TerrainWeight tw = _t_weight(terrain_coord);
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TerrainTriplanar tw = _t_triplanar();
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TerrainSample ts = _t_sample(tex, terrain_coord, tw);
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@ -279,7 +396,7 @@ vec4 terrain_texture(sampler2D tex, TerrainCoord terrain_coord)
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// *NOTE: Bottom face has not been tested
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vec3 terrain_texture_normal(sampler2D tex, TerrainCoord terrain_coord)
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{
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TerrainWeight tw = _t_weight(terrain_coord);
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TerrainTriplanar tw = _t_triplanar();
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TerrainSampleNormal ts = _t_sample_n(tex, terrain_coord, tw);
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@ -289,13 +406,92 @@ vec3 terrain_texture_normal(sampler2D tex, TerrainCoord terrain_coord)
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// Triplanar sampling of colors. Colors are converted to linear space before blending.
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vec4 terrain_texture_color(sampler2D tex, TerrainCoord terrain_coord)
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{
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TerrainWeight tw = _t_weight(terrain_coord);
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TerrainTriplanar tw = _t_triplanar();
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TerrainSample ts = _t_sample_c(tex, terrain_coord, tw);
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return ((ts.x * tw.weight.x) + (ts.y * tw.weight.y) + (ts.z * tw.weight.z)) / (tw.weight.x + tw.weight.y + tw.weight.z);
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}
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PBRMix terrain_sample_pbr(
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TerrainCoord terrain_coord
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, TerrainTriplanar tw
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, sampler2D tex_col
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, sampler2D tex_orm
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, sampler2D tex_vNt
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#if (TERRAIN_PBR_DETAIL >= TERRAIN_PBR_DETAIL_EMISSIVE)
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, sampler2D tex_emissive
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#endif
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)
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{
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PBRMix mix = init_pbr_mix();
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#define get_uv_x() _t_uv(terrain_coord[0].zw, sign(vary_vertex_normal.x))
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#define get_uv_y() _t_uv(terrain_coord[1].xy, sign(vary_vertex_normal.y))
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#define get_uv_z() _t_uv(terrain_coord[0].xy, sign(vary_vertex_normal.z))
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switch (tw.type & SAMPLE_X)
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{
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case SAMPLE_X:
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PBRMix mix_x = sample_pbr(
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get_uv_x()
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, tex_col
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, tex_orm
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, tex_vNt
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#if (TERRAIN_PBR_DETAIL >= TERRAIN_PBR_DETAIL_EMISSIVE)
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, tex_emissive
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#endif
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);
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// Triplanar-specific normal texture fix
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mix_x.vNt = _t_normal_post_x(mix_x.vNt);
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mix = mix_pbr(mix, mix_x, tw.weight.x);
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break;
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default:
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break;
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}
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switch (tw.type & SAMPLE_Y)
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{
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case SAMPLE_Y:
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PBRMix mix_y = sample_pbr(
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get_uv_y()
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, tex_col
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, tex_orm
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, tex_vNt
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#if (TERRAIN_PBR_DETAIL >= TERRAIN_PBR_DETAIL_EMISSIVE)
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, tex_emissive
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#endif
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);
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// Triplanar-specific normal texture fix
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mix_y.vNt = _t_normal_post_y(mix_y.vNt);
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mix = mix_pbr(mix, mix_y, tw.weight.y);
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break;
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default:
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break;
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}
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switch (tw.type & SAMPLE_Z)
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{
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case SAMPLE_Z:
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PBRMix mix_z = sample_pbr(
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get_uv_z()
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, tex_col
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, tex_orm
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, tex_vNt
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#if (TERRAIN_PBR_DETAIL >= TERRAIN_PBR_DETAIL_EMISSIVE)
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, tex_emissive
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#endif
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);
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// Triplanar-specific normal texture fix
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mix_z.vNt = _t_normal_post_z(mix_z.vNt);
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mix = mix_pbr(mix, mix_z, tw.weight.z);
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break;
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default:
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break;
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}
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return mix;
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}
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#elif TERRAIN_PLANAR_TEXTURE_SAMPLE_COUNT == 1
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#define TerrainCoord vec2
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vec4 terrain_texture(sampler2D tex, TerrainCoord terrain_coord)
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@ -314,6 +510,28 @@ vec4 terrain_texture_color(sampler2D tex, TerrainCoord terrain_coord)
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col.xyz = srgb_to_linear(col.xyz);
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return col;
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}
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// TODO: Implement this for the more complex triplanar case
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PBRMix terrain_sample_pbr(
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TerrainCoord terrain_coord
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, sampler2D tex_col
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, sampler2D tex_orm
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, sampler2D tex_vNt
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#if (TERRAIN_PBR_DETAIL >= TERRAIN_PBR_DETAIL_EMISSIVE)
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, sampler2D tex_emissive
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#endif
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)
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{
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return sample_pbr(
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terrain_coord
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, tex_col
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, tex_orm
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, tex_vNt
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#if (TERRAIN_PBR_DETAIL >= TERRAIN_PBR_DETAIL_EMISSIVE)
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, tex_emissive
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#endif
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);
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}
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#endif
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// The goal of _tmix_sample and related functions is to only sample textures when necessary, ignoring if the weights are low.
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