ffa9cae11c
Draw trees in two passes, opaque and transparent. This allows us to have some transparency, which is better looking, and dispense with sorting. Author: Tim Moore <timoore@redhat.com>
36 lines
1.4 KiB
GLSL
36 lines
1.4 KiB
GLSL
// Tree instance scheme:
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// vertex - local position of quad vertex.
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// normal - x y scaling, z number of varieties
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// fog coord - rotation
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// color - xyz of tree quad origin, replicated 4 times.
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varying float fogFactor;
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void main(void)
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{
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float numVarieties = gl_Normal.z;
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float texFract = floor(fract(gl_MultiTexCoord0.x) * numVarieties) / numVarieties;
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texFract += floor(gl_MultiTexCoord0.x) / numVarieties;
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float sr = sin(gl_FogCoord);
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float cr = cos(gl_FogCoord);
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gl_TexCoord[0] = vec4(texFract, gl_MultiTexCoord0.y, 0.0, 0.0);
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// scaling
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vec3 position = gl_Vertex.xyz * gl_Normal.xxy;
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// Rotation of the generic quad to specific one for the tree.
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position.xy = vec2(dot(position.xy, vec2(cr, sr)), dot(position.xy, vec2(-sr, cr)));
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position = position + gl_Color.xyz;
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gl_Position = gl_ModelViewProjectionMatrix * vec4(position,1.0);
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vec3 ecPosition = vec3(gl_ModelViewMatrix * vec4(position, 1.0));
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float n = dot(normalize(gl_LightSource[0].position.xyz), normalize(-ecPosition));
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vec3 diffuse = gl_FrontMaterial.diffuse.rgb * max(0.1, n);
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vec4 ambientColor = gl_FrontLightModelProduct.sceneColor + gl_LightSource[0].ambient * gl_FrontMaterial.ambient;
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gl_FrontColor = ambientColor + gl_LightSource[0].diffuse * vec4(diffuse, 1.0);
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float fogCoord = abs(ecPosition.z);
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fogFactor = exp( -gl_Fog.density * gl_Fog.density * fogCoord * fogCoord);
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fogFactor = clamp(fogFactor, 0.0, 1.0);
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}
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