86 lines
2.7 KiB
Plaintext
86 lines
2.7 KiB
Plaintext
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@vs vsg3
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// Shared set between most vertex shaders
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uniform ViewUniforms {
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uniform mat4 view;
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uniform mat4 proj;
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};
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out vec3 nearPoint;
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out vec3 farPoint;
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out mat4 fragView;
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out mat4 fragProj;
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// Grid position are in xy clipped space
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vec3 gridPlane[6] = vec3[](
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vec3(1, 1, 0), vec3(-1, -1, 0), vec3(-1, 1, 0),
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vec3(-1, -1, 0), vec3(1, 1, 0), vec3(1, -1, 0)
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);
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// normal vertice projection
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vec3 UnprojectPoint(float x, float y, float z, mat4 view, mat4 projection) {
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mat4 viewInv = inverse(view);
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mat4 projInv = inverse(projection);
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vec4 unprojectedPoint = viewInv * projInv * vec4(x, y, z, 1.0);
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return unprojectedPoint.xyz / unprojectedPoint.w;
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}
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void main() {
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vec3 p = gridPlane[gl_VertexIndex].xyz;
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nearPoint = UnprojectPoint(p.x, p.y, 0.0, view, proj).xyz; // unprojecting on the near plane
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farPoint = UnprojectPoint(p.x, p.y, 1.0, view, proj).xyz; // unprojecting on the far plane
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fragView = view;
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fragProj = proj;
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gl_Position = vec4(p, 1.0); // using directly the clipped coordinates
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}
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@end
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@fs fsg3
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float near = 0.01;
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float far = 100;
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in vec3 nearPoint;
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in vec3 farPoint;
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in mat4 fragView;
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in mat4 fragProj;
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out vec4 outColor;
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vec4 grid(vec3 fragPos3D, float scale, bool drawAxis) {
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vec2 coord = fragPos3D.xz * scale;
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vec2 derivative = fwidth(coord);
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vec2 grid = abs(fract(coord - 0.5) - 0.5) / derivative;
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float line = min(grid.x, grid.y);
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float minimumz = min(derivative.y, 1);
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float minimumx = min(derivative.x, 1);
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vec4 color = vec4(0.2, 0.2, 0.2, 1.0 - min(line, 1.0));
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// z axis
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if(fragPos3D.x > -0.1 * minimumx && fragPos3D.x < 0.1 * minimumx)
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color.z = 1.0;
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// x axis
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if(fragPos3D.z > -0.1 * minimumz && fragPos3D.z < 0.1 * minimumz)
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color.x = 1.0;
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return color;
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}
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float computeDepth(vec3 pos) {
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vec4 clip_space_pos = fragProj * fragView * vec4(pos.xyz, 1.0);
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return (clip_space_pos.z / clip_space_pos.w);
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}
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float computeLinearDepth(vec3 pos) {
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vec4 clip_space_pos = fragProj * fragView * vec4(pos.xyz, 1.0);
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float clip_space_depth = (clip_space_pos.z / clip_space_pos.w) * 2.0 - 1.0; // put back between -1 and 1
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float linearDepth = (2.0 * near * far) / (far + near - clip_space_depth * (far - near)); // get linear value between 0.01 and 100
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return linearDepth / far; // normalize
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}
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void main() {
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float t = -nearPoint.y / (farPoint.y - nearPoint.y);
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vec3 fragPos3D = nearPoint + t * (farPoint - nearPoint);
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gl_FragDepth = computeDepth(fragPos3D);
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float linearDepth = computeLinearDepth(fragPos3D);
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float fading = max(0, (0.5 - linearDepth));
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outColor = (grid(fragPos3D, 10, true) + grid(fragPos3D, 1, true))* float(t > 0); // adding multiple resolution for the grid
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outColor.a *= fading;
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}
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@end
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@program grid3d vsg3 fsg3
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