1 // -*- mode: c; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2; coding: utf-8-unix -*-
3 Copyright (c) 2010 Kristóf Ralovich
5 Permission is hereby granted, free of charge, to any person obtaining a copy
6 of this software and associated documentation files (the "Software"), to deal
7 in the Software without restriction, including without limitation the rights
8 to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
9 copies of the Software, and to permit persons to whom the Software is
10 furnished to do so, subject to the following conditions:
12 The above copyright notice and this permission notice shall be included in
13 all copies or substantial portions of the Software.
15 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
18 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
20 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
29 #include "shaderutil.h"
33 static int WinWidth
= 512, WinHeight
= 512;
34 static GLfloat Xrot
= 0, Yrot
= 0;
35 static int mouseGrabbed
= 0;
36 static GLuint vertShader
;
37 static GLuint fragShader
;
38 static GLuint program
;
40 static const char* vsSource
=
41 "varying vec2 rayDir;\n"
45 " rayDir = gl_MultiTexCoord0.xy - vec2(0.5,0.5);\n"
46 " gl_Position = gl_ProjectionMatrix * gl_Vertex;\n"
49 static const char* fsSource
=
50 "const float INF = 9999.9; \n"
51 "const float EPSILON = 0.00001; \n"
52 "const vec3 lightPos = vec3(0.0, 8.0, 1.0); \n"
53 "const vec4 backgroundColor = vec4(0.2,0.3,0.4,1); \n"
55 "varying vec2 rayDir; \n"
57 "uniform mat3 rot; \n"
79 "const Sphere spheres0 = Sphere( vec3(0.0,0.0,-1.0), 0.5 ); \n"
80 "const Sphere spheres1 = Sphere( vec3(-3.0,0.0,-1.0), 1.5 ); \n"
81 "const Sphere spheres2 = Sphere( vec3(0.0,3.0,-1.0), 0.5 ); \n"
82 "const Sphere spheres3 = Sphere( vec3(2.0,0.0,-1.0), 1.0 ); \n"
84 "// Mesa intel gen4 generates \"unsupported IR in fragment shader 13\" for\n"
85 "// sqrt, let's work around. \n"
87 "sqrt_hack(float f2) \n"
89 " vec3 v = vec3(f2,0.0,0.0); \n"
90 " return length(v); \n"
94 "intersect(const in Ray ray, \n"
95 " const in Sphere sph, \n"
96 " const in int idx, \n"
97 " inout Isec isec) \n"
99 " // Project both o and the sphere to the plane perpendicular to d \n"
100 " // and containing c. Let x be the point where the ray intersects \n"
101 " // the plane. If |x-c| < r, the ray intersects the sphere. \n"
102 " vec3 o = ray.orig; \n"
103 " vec3 d = ray.dir; \n"
105 " vec3 c = sph.c; \n"
106 " float r = sph.r; \n"
107 " float t = dot(c-o,n)/dot(n,d); \n"
108 " vec3 x = o+d*t; \n"
109 " float e = length(x-c); \n"
112 " // no intersection \n"
116 " // Apply Pythagorean theorem on the (intersection,x,c) triangle \n"
117 " // to get the distance between c and the intersection. \n"
118 "#ifndef BUGGY_INTEL_GEN4_GLSL \n"
119 " float f = sqrt(r*r - e*e); \n"
121 " float f = sqrt_hack(r*r - e*e); \n"
123 " float dist = t - f; \n"
126 " // inside the sphere \n"
130 " if(dist < EPSILON) \n"
133 " if(dist > isec.t) \n"
137 " isec.idx = idx; \n"
139 " isec.hit = ray.orig + ray.dir * isec.t; \n"
140 " isec.n = (isec.hit - c) / r; \n"
144 "intersect(const in Ray ray, \n"
145 " const in float max_t /*= INF*/) \n"
148 " nearest.t = max_t; \n"
149 " nearest.idx = -1; \n"
151 " intersect(ray, spheres0, 0, nearest); \n"
152 " intersect(ray, spheres1, 1, nearest); \n"
153 " intersect(ray, spheres2, 2, nearest); \n"
154 " intersect(ray, spheres3, 3, nearest); \n"
156 " return nearest; \n"
160 "idx2color(const in int idx) \n"
164 " diff = vec4(1.0, 0.0, 0.0, 0.0); \n"
165 " else if(idx == 1) \n"
166 " diff = vec4(0.0, 1.0, 0.0, 0.0); \n"
167 " else if(idx == 2) \n"
168 " diff = vec4(0.0, 0.0, 1.0, 0.0); \n"
169 " else if(idx == 3) \n"
170 " diff = vec4(1.0, 1.0, 0.0, 0.0); \n"
175 "trace0(const in Ray ray) \n"
177 " Isec isec = intersect(ray, INF); \n"
179 " if(isec.idx == -1) \n"
181 " return backgroundColor; \n"
184 " vec4 diff = idx2color(isec.idx); \n"
186 " vec3 N = isec.n; \n"
187 " vec3 L = normalize(lightPos-isec.hit); \n"
188 " vec3 camera_dir = normalize(ray.orig - isec.hit); \n"
189 " return dot(N,L)*diff + pow( \n"
190 " clamp(dot(reflect(-L,N),camera_dir),0.0,1.0),16.0); \n"
194 "trace1(const in Ray ray) \n"
196 " Isec isec = intersect(ray, INF); \n"
198 " if(isec.idx == -1) \n"
200 " return backgroundColor; \n"
203 " Ray reflRay = Ray(isec.hit, reflect(ray.dir, isec.n)); \n"
205 " vec4 reflCol = trace0(reflRay); \n"
207 " vec4 diff = idx2color(isec.idx) + reflCol; \n"
209 " vec3 N = isec.n; \n"
210 " vec3 L = normalize(lightPos-isec.hit); \n"
211 " vec3 camera_dir = normalize(ray.orig - isec.hit); \n"
212 " return dot(N,L)*diff + pow( \n"
213 " clamp(dot(reflect(-L,N),camera_dir),0.0,1.0),16.0); \n"
220 " const float z = -0.5;\n"
221 " const vec3 cameraPos = vec3(0,0,3); \n"
222 " Ray r = Ray(cameraPos, normalize(vec3(rayDir, z) * rot));\n"
223 " gl_FragColor = trace1(r);\n"
238 float rot
[9] = {1,0,0, 0,1,0, 0,0,1};
239 GLint location
= glGetUniformLocation(program
, "rot");
240 static const float m
= -10.F
;
241 static const float p
= 10.F
;
242 static const float d
= -0.5F
;
244 glUseProgram(program
);
245 glUniformMatrix3fv(location
, 1, 0, rot
);
249 glTexCoord2f(0.0F
, 0.0F
); glVertex3f(m
, m
, d
);
250 glTexCoord2f(1.0F
, 0.0F
); glVertex3f(p
, m
, d
);
251 glTexCoord2f(1.0F
, 1.0F
); glVertex3f(p
, p
, d
);
252 glTexCoord2f(0.0F
, 1.0F
); glVertex3f(m
, p
, d
);
260 static int frames
= 0;
265 t1
= glutGet(GLUT_ELAPSED_TIME
);
266 dt
= (float)(t1
-t0
)/1000.0F
;
269 float fps
= (float)frames
/ dt
;
270 printf("%f FPS (%d frames in %f seconds)\n", fps
, frames
, dt
);
279 Reshape(int width
, int height
)
283 glViewport(0, 0, width
, height
);
284 glMatrixMode(GL_PROJECTION
);
286 glOrtho(-10, 10, -10, 10, -1, 1);
287 glMatrixMode(GL_MODELVIEW
);
293 Key(unsigned char key
, int x
, int y
)
299 glutDestroyWindow(Win
);
314 Xrot
= (float)(x
- WinWidth
/2) / scale
;
315 Yrot
= (float)(y
- WinHeight
/2) / scale
;
316 printf("%4.2f %4.2f\n", Xrot
, Yrot
);
323 mouse(int button
, int state
, int x
, int y
)
325 if(state
== GLUT_DOWN
)
327 mouseGrabbed
= !mouseGrabbed
;
335 glDisable(GL_DEPTH_TEST
);
337 if(!ShadersSupported())
339 fprintf(stderr
, "Shaders are not supported!\n");
343 vertShader
= CompileShaderText(GL_VERTEX_SHADER
, vsSource
);
344 fragShader
= CompileShaderText(GL_FRAGMENT_SHADER
, fsSource
);
345 program
= LinkShaders(vertShader
, fragShader
);
348 if(glGetError() != 0)
350 fprintf(stderr
, "Shaders were not loaded!\n");
354 if(!glIsShader(vertShader
))
356 fprintf(stderr
, "Vertex shader failed!\n");
360 if(!glIsProgram(program
))
362 fprintf(stderr
, "Shader program failed!\n");
366 printf("GL_RENDERER = %s\n",(const char *) glGetString(GL_RENDERER
));
371 main(int argc
, char *argv
[])
373 glutInitWindowSize(WinWidth
, WinHeight
);
374 glutInit(&argc
, argv
);
375 glutInitDisplayMode(GLUT_RGB
| GLUT_DOUBLE
| GLUT_DEPTH
);
376 Win
= glutCreateWindow(argv
[0]);
378 glutReshapeFunc(Reshape
);
379 glutKeyboardFunc(Key
);
380 glutDisplayFunc(Draw
);
381 glutMouseFunc(mouse
);
382 glutPassiveMotionFunc(drag
);