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grass_shaders_source.h
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1 #ifndef GRASS_SHADERS_SOURCE_H
2 #define GRASS_SHADERS_SOURCE_H
3 
4 
5 const char * lowDetailVertexShaderSource =
6 " varying float angle; \n"
7 " varying float distance; \n"
8 " uniform float maxVisibility; \n"
9 " uniform float minVisibility; \n"
10 " void main() \n"
11 " { \n"
12 " gl_Position = ftransform(); \n"
13 " angle = 1.0 - max(0.0, dot(vec3(0.0, 0.0, 1.0), gl_NormalMatrix * gl_Normal)); \n"
14 " distance = smoothstep(minVisibility, maxVisibility, \n"
15 " length(gl_ModelViewMatrix * gl_Vertex)); \n"
16 " gl_TexCoord[0].st = gl_MultiTexCoord0.st; \n"
17 " } \n";
18 
19 
20 const char * lowDetailFragmentShaderSource =
21 " uniform sampler2D far_soil; \n"
22 " uniform sampler2D far_grass; \n"
23 " varying float angle; \n"
24 " varying float distance; \n"
25 " void main( void ) \n"
26 " { \n"
27 " vec4 soilColor = texture2D(far_soil, gl_TexCoord[0].st, -2.0); \n"
28 " vec4 grassColor = texture2D(far_grass, gl_TexCoord[0].st, -2.0); \n"
29 " gl_FragColor = mix(soilColor, grassColor, distance); \n"
30 " } \n";
31 
32 
33 
34 const char * detailedVertexShaderSource =
35 " // uniforms \n"
36 " uniform float osg_FrameTime; \n"
37 " uniform float maxVisibility; \n"
38 " uniform float minVisibility; \n"
39 " \n"
40 " // constants \n"
41 " const vec4 swingConstants1 = vec4(-10.45201, 6.78566, 3.45622, -8.12345); \n"
42 " const vec4 swingConstants2 = vec4(0.37698, 2.67035, 0.47124, 1.69646); \n"
43 " const vec4 swingConstants3 = vec4(0.05457, 0.08145, 0.14247, 0.05442); \n"
44 " \n"
45 " // attributes \n"
46 " attribute mat3 bladeSpaceBase; // (up, orientation, side) \n"
47 " attribute vec4 look; // (width, height, topColor, bottomColor) \n"
48 " attribute vec4 position; // (x, y, z, bend) \n"
49 " \n"
50 " \n"
51 " void main( void ) \n"
52 " { \n"
53 " // compute swing phase of the blade \n"
54 " vec4 swingvec = sin((osg_FrameTime + position.x + position.y + position.z) \n"
55 " * swingConstants1 + swingConstants2); \n"
56 " float bend = position.w + dot(swingvec, swingConstants3); \n"
57 " \n"
58 " // ensure bend is not zero (we will divide by it) \n"
59 " if(bend == 0.0) \n"
60 " bend = 0.00001; \n"
61 " \n"
62 " // compute the angle of the blade \n"
63 " float angle = bend * gl_Vertex.y; \n"
64 " \n"
65 " vec3 bladePoint; \n"
66 " \n"
67 " // normalize previous results and add the width of blade in current point \n"
68 " bladePoint.xy = vec2(sin(angle), 1.0-cos(angle)) * (look.y / bend); \n"
69 " bladePoint.z = look.x * gl_Vertex.x; \n"
70 " \n"
71 " vec4 tempPosition = vec4(position.xyz, 1.0); \n"
72 " \n"
73 " // compute the distance to the root of the blade \n"
74 " float distance = length(gl_ModelViewMatrix * tempPosition); \n"
75 " \n"
76 " // compute scale of the whole blade \n"
77 " float scale = (1.0 - smoothstep(minVisibility, maxVisibility, distance)); \n"
78 " \n"
79 " // compute the position of this point of the blade \n"
80 " tempPosition.xyz += bladeSpaceBase * (bladePoint * scale); \n"
81 " gl_Position = gl_ModelViewProjectionMatrix * tempPosition; \n"
82 " \n"
83 " // forward texture coordinates to fragment shader \n"
84 " gl_TexCoord[0].y = gl_Vertex.y; \n"
85 " gl_TexCoord[0].x = sign(gl_Vertex.x)*0.49 + 0.5; \n"
86 " gl_TexCoord[0].z = scale; \n"
87 " } \n";
88 
89 
90 const char * detailedFragmentShaderSource =
91 " uniform sampler2D texture; \n"
92 " uniform vec4 neutralColor; \n"
93 " void main( void ) \n"
94 " { \n"
95 " gl_FragColor = mix( neutralColor, \n"
96 " texture2D(texture, gl_TexCoord[0].xy), \n"
97 " gl_TexCoord[0].z \n"
98 " ); \n"
99 " } \n";
100 
101 
102 
103 #endif // GRASS_SHADERS_SOURCE_H