75 lines
1.8 KiB
GLSL
75 lines
1.8 KiB
GLSL
#version 330 core
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layout (triangles) in;
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layout (triangle_strip) out;
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uniform mat4 Model;
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in vec2 gtexCoord[];
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in vec3 gnormCoord[];
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in vec3 gWorldPos[];
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out vec2 texCoord;
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out vec3 normCoord;
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out vec3 WorldPos;
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out mat3 TBN;
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void main(void)
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{
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// Calculate Normal Map stuff
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// Real space triangle
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vec3 p1 = gl_in[0].gl_Position.xyz;
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vec3 p2 = gl_in[1].gl_Position.xyz;
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vec3 p3 = gl_in[2].gl_Position.xyz;
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// Normal texture space triangle
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vec2 uv1 = gtexCoord[0];
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vec2 uv2 = gtexCoord[1];
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vec2 uv3 = gtexCoord[2];
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// Calculate edge translation vectors duv stands for delta uv
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vec3 edge1 = p2 - p1;
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vec3 edge2 = p3 - p1;
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vec2 duv1 = uv2 - uv1;
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vec2 duv2 = uv3 - uv1;
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// Calculation of tangents and bi tangents
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// [ddTxBxTyByTzBz]=1ΔU1ΔV2−ΔU2ΔV1[ΔV2−ΔU2−ΔV1ΔU1][E1xE2xE1yE2yE1zE2z]
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// https://learnopengl.com/Advanced-Lighting/Normal-Mapping
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float f = 1.0 / (duv1.x * duv2.y - duv2.x * duv1.y);
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float tx = f * (duv2.y * edge1.x - duv1.y * edge2.x);
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float ty = f * (duv2.y * edge1.y - duv1.y * edge2.y);
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float tz = f * (duv2.y * edge1.z - duv1.y * edge2.z);
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vec3 tangent = vec3(tx, ty, tz);
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//Calculate TBN
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vec3 T = normalize(vec3(Model * vec4(tangent, 0.0)));
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vec3 N = normalize(vec3(Model * vec4(gnormCoord[0], 0.0)));
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vec3 B = cross(N, T);
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TBN = mat3(T, B, N);
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// send data to Fragment Shader
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gl_Position = gl_in[0].gl_Position;
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texCoord = gtexCoord[0];
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normCoord = gnormCoord[0];
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WorldPos = gWorldPos[0];
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EmitVertex();
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gl_Position = gl_in[1].gl_Position;
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texCoord = gtexCoord[1];
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normCoord = gnormCoord[1];
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WorldPos = gWorldPos[1];
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EmitVertex();
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gl_Position = gl_in[2].gl_Position;
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texCoord = gtexCoord[2];
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normCoord = gnormCoord[2];
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WorldPos = gWorldPos[2];
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EmitVertex();
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EndPrimitive();
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};
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