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progs/glsl: improve the mouse drag/rotate code a little
[mesa.git] / progs / glsl / fsraytrace.c
1 /* -*- mode: c; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2; coding: utf-8-unix -*- */
2 /*
3 Copyright (c) 2010 Kristóf Ralovich
4
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:
11
12 The above copyright notice and this permission notice shall be included in
13 all copies or substantial portions of the Software.
14
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
21 THE SOFTWARE.
22 */
23
24
25 #include <stdio.h>
26 #include <stdlib.h>
27 #include <GL/glew.h>
28 #include <GL/glut.h>
29 #include "shaderutil.h"
30 #include <math.h>
31
32 static int Win;
33 static int WinWidth = 512, WinHeight = 512;
34 static int mouseGrabbed = 0;
35 static GLuint vertShader;
36 static GLuint fragShader;
37 static GLuint program;
38 static float rot[9] = {1,0,0, 0,1,0, 0,0,1};
39
40 static const char* vsSource =
41 "varying vec2 rayDir; \n"
42 " \n"
43 "void main() \n"
44 "{ \n"
45 " rayDir = gl_MultiTexCoord0.xy - vec2(0.5,0.5); \n"
46 " gl_Position = gl_ProjectionMatrix * gl_Vertex; \n"
47 "}\n";
48
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"
54 " \n"
55 "varying vec2 rayDir; \n"
56 " \n"
57 "uniform mat3 rot; \n"
58 " \n"
59 "struct Ray \n"
60 "{ \n"
61 "vec3 orig; \n"
62 "vec3 dir; \n"
63 "}; \n"
64 " \n"
65 "struct Sphere \n"
66 "{ \n"
67 " vec3 c; \n"
68 " float r; \n"
69 "}; \n"
70 " \n"
71 "struct Isec \n"
72 "{ \n"
73 " float t; \n"
74 " int idx; \n"
75 " vec3 hit; \n"
76 " vec3 n; \n"
77 "}; \n"
78 " \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"
83 " \n"
84 "// Mesa intel gen4 generates \"unsupported IR in fragment shader 13\" for\n"
85 "// sqrt, let's work around. \n"
86 "float \n"
87 "sqrt_hack(float f2) \n"
88 "{ \n"
89 " vec3 v = vec3(f2,0.0,0.0); \n"
90 " return length(v); \n"
91 "} \n"
92 " \n"
93 "void \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"
98 "{ \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"
104 " vec3 n = -d; \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"
110 " if(e > r) \n"
111 " { \n"
112 " // no intersection \n"
113 " return; \n"
114 " } \n"
115 " \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"
120 "#else \n"
121 " float f = sqrt_hack(r*r - e*e); \n"
122 "#endif \n"
123 " float dist = t - f; \n"
124 " if(dist < 0.0) \n"
125 " { \n"
126 " // inside the sphere \n"
127 " return; \n"
128 " } \n"
129 " \n"
130 " if(dist < EPSILON) \n"
131 " return; \n"
132 " \n"
133 " if(dist > isec.t) \n"
134 " return; \n"
135 " \n"
136 " isec.t = dist; \n"
137 " isec.idx = idx; \n"
138 " \n"
139 " isec.hit = ray.orig + ray.dir * isec.t; \n"
140 " isec.n = (isec.hit - c) / r; \n"
141 "} \n"
142 " \n"
143 "Isec \n"
144 "intersect(const in Ray ray, \n"
145 " const in float max_t /*= INF*/) \n"
146 "{ \n"
147 " Isec nearest; \n"
148 " nearest.t = max_t; \n"
149 " nearest.idx = -1; \n"
150 " \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"
155 " \n"
156 " return nearest; \n"
157 "} \n"
158 " \n"
159 "vec4 \n"
160 "idx2color(const in int idx) \n"
161 "{ \n"
162 " vec4 diff; \n"
163 " if(idx == 0) \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"
171 " return diff; \n"
172 "} \n"
173 " \n"
174 "vec4 \n"
175 "trace0(const in Ray ray) \n"
176 "{ \n"
177 " Isec isec = intersect(ray, INF); \n"
178 " \n"
179 " if(isec.idx == -1) \n"
180 " { \n"
181 " return backgroundColor; \n"
182 " } \n"
183 " \n"
184 " vec4 diff = idx2color(isec.idx); \n"
185 " \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"
191 "} \n"
192 " \n"
193 "vec4 \n"
194 "trace1(const in Ray ray) \n"
195 "{ \n"
196 " Isec isec = intersect(ray, INF); \n"
197 " \n"
198 " if(isec.idx == -1) \n"
199 " { \n"
200 " return backgroundColor; \n"
201 " } \n"
202 " \n"
203 " Ray reflRay = Ray(isec.hit, reflect(ray.dir, isec.n)); \n"
204 " \n"
205 " vec4 reflCol = trace0(reflRay); \n"
206 " \n"
207 " vec4 diff = idx2color(isec.idx) + reflCol; \n"
208 " \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"
214 "} \n"
215 " \n"
216 "void main() \n"
217 "{ \n"
218 " const float z = -0.5; \n"
219 " const vec3 cameraPos = vec3(0,0,3); \n"
220 " Ray r = Ray(cameraPos, normalize(vec3(rayDir, z) * rot)); \n"
221 " gl_FragColor = trace1(r); \n"
222 "}\n";
223
224 static inline
225 float
226 deg2rad(const float degree)
227 {
228 return( degree * 0.017453292519943295769236907684886F);
229 }
230
231 static inline void
232 rotate_xy(float* mat3, const float degreesAroundX, const float degreesAroundY)
233 {
234 const float rad1 = deg2rad(degreesAroundX);
235 const float c1 = cosf(rad1);
236 const float s1 = sinf(rad1);
237 const float rad2 = deg2rad(degreesAroundY);
238 const float c2 = cosf(rad2);
239 const float s2 = sinf(rad2);
240 mat3[0] = c2; mat3[3] = 0.0F; mat3[6] = s2;
241 mat3[1] = s1*s2; mat3[4] = c1; mat3[7] = -s1*c2;
242 mat3[2] = -c1*s2;mat3[5] = s1; mat3[8] = c1*c2;
243 }
244
245 static inline void
246 identity(float* mat3)
247 {
248 mat3[0] = 1.0F; mat3[3] = 0.0F; mat3[6] = 0.0F;
249 mat3[1] = 0.0F; mat3[4] = 1.0F; mat3[7] = 0.0F;
250 mat3[2] = 0.0F; mat3[5] = 0.0F; mat3[8] = 1.0F;
251 }
252
253 static void
254 Draw(void)
255 {
256 GLint location = glGetUniformLocation(program, "rot");
257 static const float m = -10.F;
258 static const float p = 10.F;
259 static const float d = -0.5F;
260
261 glUseProgram(program);
262 glUniformMatrix3fv(location, 1, 0, rot);
263
264 glBegin(GL_QUADS);
265 {
266 glTexCoord2f(0.0F, 0.0F); glVertex3f(m, m, d);
267 glTexCoord2f(1.0F, 0.0F); glVertex3f(p, m, d);
268 glTexCoord2f(1.0F, 1.0F); glVertex3f(p, p, d);
269 glTexCoord2f(0.0F, 1.0F); glVertex3f(m, p, d);
270 }
271 glEnd();
272 glUseProgram(0);
273
274 glutSwapBuffers();
275
276 {
277 static int frames = 0;
278 static int t0 = 0;
279 static int t1 = 0;
280 float dt;
281 frames++;
282 t1 = glutGet(GLUT_ELAPSED_TIME);
283 dt = (float)(t1-t0)/1000.0F;
284 if(dt >= 5.0F)
285 {
286 float fps = (float)frames / dt;
287 printf("%f FPS (%d frames in %f seconds)\n", fps, frames, dt);
288 frames = 0;
289 t0 = t1;
290 }
291 }
292 }
293
294
295 static void
296 Reshape(int width, int height)
297 {
298 WinWidth = width;
299 WinHeight = height;
300 glViewport(0, 0, width, height);
301 glMatrixMode(GL_PROJECTION);
302 glLoadIdentity();
303 glOrtho(-10, 10, -10, 10, -1, 1);
304 glMatrixMode(GL_MODELVIEW);
305 glLoadIdentity();
306 }
307
308
309 static void
310 Key(unsigned char key, int x, int y)
311 {
312 (void) x;
313 (void) y;
314 switch (key) {
315 case 27:
316 glutDestroyWindow(Win);
317 exit(0);
318 break;
319 }
320 glutPostRedisplay();
321 }
322
323
324 static
325 void
326 drag(int x, int y)
327 {
328 float scale = 1.5F;
329 if(mouseGrabbed)
330 {
331 static GLfloat xRot = 0, yRot = 0;
332 xRot = (float)(x - WinWidth/2) / scale;
333 yRot = (float)(y - WinHeight/2) / scale;
334 identity(rot);
335 rotate_xy(rot, yRot, xRot);
336 glutPostRedisplay();
337 }
338 }
339
340
341 static
342 void
343 mouse(int button, int state, int x, int y)
344 {
345 mouseGrabbed = (state == GLUT_DOWN);
346 }
347
348
349 static void
350 Init(void)
351 {
352 glDisable(GL_DEPTH_TEST);
353
354 if(!ShadersSupported())
355 {
356 fprintf(stderr, "Shaders are not supported!\n");
357 exit(-1);
358 }
359
360 vertShader = CompileShaderText(GL_VERTEX_SHADER, vsSource);
361 fragShader = CompileShaderText(GL_FRAGMENT_SHADER, fsSource);
362 program = LinkShaders(vertShader, fragShader);
363 glUseProgram(0);
364
365 if(glGetError() != 0)
366 {
367 fprintf(stderr, "Shaders were not loaded!\n");
368 exit(-1);
369 }
370
371 if(!glIsShader(vertShader))
372 {
373 fprintf(stderr, "Vertex shader failed!\n");
374 exit(-1);
375 }
376
377 if(!glIsProgram(program))
378 {
379 fprintf(stderr, "Shader program failed!\n");
380 exit(-1);
381 }
382
383 printf("GL_RENDERER = %s\n",(const char *) glGetString(GL_RENDERER));
384 }
385
386
387 int
388 main(int argc, char *argv[])
389 {
390 glutInitWindowSize(WinWidth, WinHeight);
391 glutInit(&argc, argv);
392 glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);
393 Win = glutCreateWindow(argv[0]);
394 glewInit();
395 glutReshapeFunc(Reshape);
396 glutKeyboardFunc(Key);
397 glutDisplayFunc(Draw);
398 glutMouseFunc(mouse);
399 glutMotionFunc(drag);
400 glutIdleFunc(Draw);
401 Init();
402 glutMainLoop();
403 return 0;
404 }
405