-static char vertexShaderSource[] =
- "#version 120\n"
- "\n"
- "varying float fogFactor;\n"
- "attribute vec3 usrAttr1;\n"
- "attribute vec3 usrAttr2;\n"
- "float textureIndexX = usrAttr1.r;\n"
- "float textureIndexY = usrAttr1.g;\n"
- "float wScale = usrAttr1.b;\n"
- "float hScale = usrAttr2.r;\n"
- "float shade = usrAttr2.g;\n"
- "float cloud_height = usrAttr2.b;\n"
- "void main(void)\n"
- "{\n"
- " gl_TexCoord[0] = gl_MultiTexCoord0 + vec4(textureIndexX, textureIndexY, 0.0, 0.0);\n"
- " vec4 ep = gl_ModelViewMatrixInverse * vec4(0.0,0.0,0.0,1.0);\n"
- " vec4 l = gl_ModelViewMatrixInverse * vec4(0.0,0.0,1.0,1.0);\n"
- " vec3 u = normalize(ep.xyz - l.xyz);\n"
-// Find a rotation matrix that rotates 1,0,0 into u. u, r and w are
-// the columns of that matrix.
- " vec3 absu = abs(u);\n"
- " vec3 r = normalize(vec3(-u.y, u.x, 0));\n"
- " vec3 w = cross(u, r);\n"
-// Do the matrix multiplication by [ u r w pos]. Assume no
-// scaling in the homogeneous component of pos.
- " gl_Position = vec4(0.0, 0.0, 0.0, 1.0);\n"
- " gl_Position.xyz = gl_Vertex.x * u * wScale;\n"
- " gl_Position.xyz += gl_Vertex.y * r * hScale;\n"
- " gl_Position.xyz += gl_Vertex.z * w;\n"
- " gl_Position.xyz += gl_Color.xyz;\n"
-// Determine a lighting normal based on the vertex position from the
-// center of the cloud, so that sprite on the opposite side of the cloud to the sun are darker.
- " float n = dot(normalize(gl_LightSource[0].position.xyz), normalize(mat3x3(gl_ModelViewMatrix) * gl_Position.xyz));\n"
-// Determine the position - used for fog and shading calculations
- " vec3 ecPosition = vec3(gl_ModelViewMatrix * gl_Position);\n"
- " float fogCoord = abs(ecPosition.z);\n"
- " float fract = smoothstep(0.0, cloud_height, gl_Position.z + cloud_height);\n"
-// Final position of the sprite
- " gl_Position = gl_ModelViewProjectionMatrix * gl_Position;\n"
-// Limit the normal range from [0,1.0], and apply the shading (vertical factor)
- " n = min(smoothstep(-0.5, 0.5, n), shade * (1.0 - fract) + fract);\n"
-// This lighting normal is then used to mix between almost pure ambient (0) and diffuse (1.0) light
- " vec4 backlight = 0.9 * gl_LightSource[0].ambient + 0.1 * gl_LightSource[0].diffuse;\n"
- " gl_FrontColor = mix(backlight, gl_LightSource[0].diffuse, n);\n"
- " gl_FrontColor += gl_FrontLightModelProduct.sceneColor;\n"
-// As we get within 100m of the sprite, it is faded out. Equally at large distances it also fades out.
- " gl_FrontColor.a = min(smoothstep(10.0, 100.0, fogCoord), 1 - smoothstep(15000.0, 20000.0, fogCoord));\n"
- " gl_BackColor = gl_FrontColor;\n"
-// Fog doesn't affect clouds as much as other objects.
- " fogFactor = exp( -gl_Fog.density * fogCoord * 0.5);\n"
- " fogFactor = clamp(fogFactor, 0.0, 1.0);\n"
- "}\n";
-
-static char fragmentShaderSource[] =
- "uniform sampler2D baseTexture; \n"
- "varying float fogFactor;\n"
- "\n"
- "void main(void)\n"
- "{\n"
- " vec4 base = texture2D( baseTexture, gl_TexCoord[0].st);\n"
- " vec4 finalColor = base * gl_Color;\n"
- " gl_FragColor.rgb = mix(gl_Fog.color.rgb, finalColor.rgb, fogFactor );\n"
- " gl_FragColor.a = finalColor.a;\n"
- "}\n";
-