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-rw-r--r--progs/glsl/fsraytrace.c388
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diff --git a/progs/glsl/fsraytrace.c b/progs/glsl/fsraytrace.c
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+/* -*- mode: c; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2; coding: utf-8-unix -*- */
+/*
+ Copyright (c) 2010 Kristóf Ralovich
+
+ Permission is hereby granted, free of charge, to any person obtaining a copy
+ of this software and associated documentation files (the "Software"), to deal
+ in the Software without restriction, including without limitation the rights
+ to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ copies of the Software, and to permit persons to whom the Software is
+ furnished to do so, subject to the following conditions:
+
+ The above copyright notice and this permission notice shall be included in
+ all copies or substantial portions of the Software.
+
+ THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ THE SOFTWARE.
+*/
+
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <GL/glew.h>
+#include <GL/glut.h>
+#include "shaderutil.h"
+
+
+static int Win;
+static int WinWidth = 512, WinHeight = 512;
+static GLfloat Xrot = 0, Yrot = 0;
+static int mouseGrabbed = 0;
+static GLuint vertShader;
+static GLuint fragShader;
+static GLuint program;
+
+static const char* vsSource =
+ "varying vec2 rayDir;\n"
+ "\n"
+ "void main()\n"
+ "{\n"
+ " rayDir = gl_MultiTexCoord0.xy - vec2(0.5,0.5);\n"
+ " gl_Position = gl_ProjectionMatrix * gl_Vertex;\n"
+ "}\n";
+
+static const char* fsSource =
+ "const float INF = 9999.9; \n"
+ "const float EPSILON = 0.00001; \n"
+ "const vec3 lightPos = vec3(0.0, 8.0, 1.0); \n"
+ "const vec4 backgroundColor = vec4(0.2,0.3,0.4,1); \n"
+ " \n"
+ "varying vec2 rayDir; \n"
+ " \n"
+ "uniform mat3 rot; \n"
+ " \n"
+ "struct Ray \n"
+ "{ \n"
+ "vec3 orig; \n"
+ "vec3 dir; \n"
+ "}; \n"
+ " \n"
+ "struct Sphere \n"
+ "{ \n"
+ " vec3 c; \n"
+ " float r; \n"
+ "}; \n"
+ " \n"
+ "struct Isec \n"
+ "{ \n"
+ " float t; \n"
+ " int idx; \n"
+ " vec3 hit; \n"
+ " vec3 n; \n"
+ "}; \n"
+ " \n"
+ "const Sphere spheres0 = Sphere( vec3(0.0,0.0,-1.0), 0.5 ); \n"
+ "const Sphere spheres1 = Sphere( vec3(-3.0,0.0,-1.0), 1.5 ); \n"
+ "const Sphere spheres2 = Sphere( vec3(0.0,3.0,-1.0), 0.5 ); \n"
+ "const Sphere spheres3 = Sphere( vec3(2.0,0.0,-1.0), 1.0 ); \n"
+ " \n"
+ "// Mesa intel gen4 generates \"unsupported IR in fragment shader 13\" for\n"
+ "// sqrt, let's work around. \n"
+ "float \n"
+ "sqrt_hack(float f2) \n"
+ "{ \n"
+ " vec3 v = vec3(f2,0.0,0.0); \n"
+ " return length(v); \n"
+ "} \n"
+ " \n"
+ "void \n"
+ "intersect(const in Ray ray, \n"
+ " const in Sphere sph, \n"
+ " const in int idx, \n"
+ " inout Isec isec) \n"
+ "{ \n"
+ " // Project both o and the sphere to the plane perpendicular to d \n"
+ " // and containing c. Let x be the point where the ray intersects \n"
+ " // the plane. If |x-c| < r, the ray intersects the sphere. \n"
+ " vec3 o = ray.orig; \n"
+ " vec3 d = ray.dir; \n"
+ " vec3 n = -d; \n"
+ " vec3 c = sph.c; \n"
+ " float r = sph.r; \n"
+ " float t = dot(c-o,n)/dot(n,d); \n"
+ " vec3 x = o+d*t; \n"
+ " float e = length(x-c); \n"
+ " if(e > r) \n"
+ " { \n"
+ " // no intersection \n"
+ " return; \n"
+ " } \n"
+ " \n"
+ " // Apply Pythagorean theorem on the (intersection,x,c) triangle \n"
+ " // to get the distance between c and the intersection. \n"
+ "#ifndef BUGGY_INTEL_GEN4_GLSL \n"
+ " float f = sqrt(r*r - e*e); \n"
+ "#else \n"
+ " float f = sqrt_hack(r*r - e*e); \n"
+ "#endif \n"
+ " float dist = t - f; \n"
+ " if(dist < 0.0) \n"
+ " { \n"
+ " // inside the sphere \n"
+ " return; \n"
+ " } \n"
+ " \n"
+ " if(dist < EPSILON) \n"
+ " return; \n"
+ " \n"
+ " if(dist > isec.t) \n"
+ " return; \n"
+ " \n"
+ " isec.t = dist; \n"
+ " isec.idx = idx; \n"
+ " \n"
+ " isec.hit = ray.orig + ray.dir * isec.t; \n"
+ " isec.n = (isec.hit - c) / r; \n"
+ "} \n"
+ " \n"
+ "Isec \n"
+ "intersect(const in Ray ray, \n"
+ " const in float max_t /*= INF*/) \n"
+ "{ \n"
+ " Isec nearest; \n"
+ " nearest.t = max_t; \n"
+ " nearest.idx = -1; \n"
+ " \n"
+ " intersect(ray, spheres0, 0, nearest); \n"
+ " intersect(ray, spheres1, 1, nearest); \n"
+ " intersect(ray, spheres2, 2, nearest); \n"
+ " intersect(ray, spheres3, 3, nearest); \n"
+ " \n"
+ " return nearest; \n"
+ "} \n"
+ " \n"
+ "vec4 \n"
+ "idx2color(const in int idx) \n"
+ "{ \n"
+ " vec4 diff; \n"
+ " if(idx == 0) \n"
+ " diff = vec4(1.0, 0.0, 0.0, 0.0); \n"
+ " else if(idx == 1) \n"
+ " diff = vec4(0.0, 1.0, 0.0, 0.0); \n"
+ " else if(idx == 2) \n"
+ " diff = vec4(0.0, 0.0, 1.0, 0.0); \n"
+ " else if(idx == 3) \n"
+ " diff = vec4(1.0, 1.0, 0.0, 0.0); \n"
+ " return diff; \n"
+ "} \n"
+ " \n"
+ "vec4 \n"
+ "trace0(const in Ray ray) \n"
+ "{ \n"
+ " Isec isec = intersect(ray, INF); \n"
+ " \n"
+ " if(isec.idx == -1) \n"
+ " { \n"
+ " return backgroundColor; \n"
+ " } \n"
+ " \n"
+ " vec4 diff = idx2color(isec.idx); \n"
+ " \n"
+ " vec3 N = isec.n; \n"
+ " vec3 L = normalize(lightPos-isec.hit); \n"
+ " vec3 camera_dir = normalize(ray.orig - isec.hit); \n"
+ " return dot(N,L)*diff + pow( \n"
+ " clamp(dot(reflect(-L,N),camera_dir),0.0,1.0),16.0); \n"
+ "} \n"
+ " \n"
+ "vec4 \n"
+ "trace1(const in Ray ray) \n"
+ "{ \n"
+ " Isec isec = intersect(ray, INF); \n"
+ " \n"
+ " if(isec.idx == -1) \n"
+ " { \n"
+ " return backgroundColor; \n"
+ " } \n"
+ " \n"
+ " Ray reflRay = Ray(isec.hit, reflect(ray.dir, isec.n)); \n"
+ " \n"
+ " vec4 reflCol = trace0(reflRay); \n"
+ " \n"
+ " vec4 diff = idx2color(isec.idx) + reflCol; \n"
+ " \n"
+ " vec3 N = isec.n; \n"
+ " vec3 L = normalize(lightPos-isec.hit); \n"
+ " vec3 camera_dir = normalize(ray.orig - isec.hit); \n"
+ " return dot(N,L)*diff + pow( \n"
+ " clamp(dot(reflect(-L,N),camera_dir),0.0,1.0),16.0); \n"
+ "} \n"
+ " \n"
+ "\n"
+ "void\n"
+ "main()\n"
+ "{\n"
+ " const float z = -0.5;\n"
+ " const vec3 cameraPos = vec3(0,0,3); \n"
+ " Ray r = Ray(cameraPos, normalize(vec3(rayDir, z) * rot));\n"
+ " gl_FragColor = trace1(r);\n"
+ "}\n";
+
+
+
+static void
+Idle(void)
+{
+ glutPostRedisplay();
+}
+
+
+static void
+Draw(void)
+{
+ float rot[9] = {1,0,0, 0,1,0, 0,0,1};
+ GLint location = glGetUniformLocation(program, "rot");
+ static const float m = -10.F;
+ static const float p = 10.F;
+ static const float d = -0.5F;
+
+ glUseProgram(program);
+ glUniformMatrix3fv(location, 1, 0, rot);
+
+ glBegin(GL_QUADS);
+ {
+ glTexCoord2f(0.0F, 0.0F); glVertex3f(m, m, d);
+ glTexCoord2f(1.0F, 0.0F); glVertex3f(p, m, d);
+ glTexCoord2f(1.0F, 1.0F); glVertex3f(p, p, d);
+ glTexCoord2f(0.0F, 1.0F); glVertex3f(m, p, d);
+ }
+ glEnd();
+ glUseProgram(0);
+
+ glutSwapBuffers();
+
+ {
+ static int frames = 0;
+ static int t0 = 0;
+ static int t1 = 0;
+ float dt;
+ frames++;
+ t1 = glutGet(GLUT_ELAPSED_TIME);
+ dt = (float)(t1-t0)/1000.0F;
+ if(dt >= 5.0F)
+ {
+ float fps = (float)frames / dt;
+ printf("%f FPS (%d frames in %f seconds)\n", fps, frames, dt);
+ frames = 0;
+ t0 = t1;
+ }
+ }
+}
+
+
+static void
+Reshape(int width, int height)
+{
+ WinWidth = width;
+ WinHeight = height;
+ glViewport(0, 0, width, height);
+ glMatrixMode(GL_PROJECTION);
+ glLoadIdentity();
+ glOrtho(-10, 10, -10, 10, -1, 1);
+ glMatrixMode(GL_MODELVIEW);
+ glLoadIdentity();
+}
+
+
+static void
+Key(unsigned char key, int x, int y)
+{
+ (void) x;
+ (void) y;
+ switch (key) {
+ case 27:
+ glutDestroyWindow(Win);
+ exit(0);
+ break;
+ }
+ glutPostRedisplay();
+}
+
+
+static
+void
+drag(int x, int y)
+{
+ float scale = 1.5F;
+ if(mouseGrabbed)
+ {
+ Xrot = (float)(x - WinWidth/2) / scale;
+ Yrot = (float)(y - WinHeight/2) / scale;
+ printf("%4.2f %4.2f\n", Xrot, Yrot);
+ }
+}
+
+
+static
+void
+mouse(int button, int state, int x, int y)
+{
+ if(state == GLUT_DOWN)
+ {
+ mouseGrabbed = !mouseGrabbed;
+ }
+}
+
+
+static void
+Init(void)
+{
+ glDisable(GL_DEPTH_TEST);
+
+ if(!ShadersSupported())
+ {
+ fprintf(stderr, "Shaders are not supported!\n");
+ exit(-1);
+ }
+
+ vertShader = CompileShaderText(GL_VERTEX_SHADER, vsSource);
+ fragShader = CompileShaderText(GL_FRAGMENT_SHADER, fsSource);
+ program = LinkShaders(vertShader, fragShader);
+ glUseProgram(0);
+
+ if(glGetError() != 0)
+ {
+ fprintf(stderr, "Shaders were not loaded!\n");
+ exit(-1);
+ }
+
+ if(!glIsShader(vertShader))
+ {
+ fprintf(stderr, "Vertex shader failed!\n");
+ exit(-1);
+ }
+
+ if(!glIsProgram(program))
+ {
+ fprintf(stderr, "Shader program failed!\n");
+ exit(-1);
+ }
+
+ printf("GL_RENDERER = %s\n",(const char *) glGetString(GL_RENDERER));
+}
+
+
+int
+main(int argc, char *argv[])
+{
+ glutInitWindowSize(WinWidth, WinHeight);
+ glutInit(&argc, argv);
+ glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);
+ Win = glutCreateWindow(argv[0]);
+ glewInit();
+ glutReshapeFunc(Reshape);
+ glutKeyboardFunc(Key);
+ glutDisplayFunc(Draw);
+ glutMouseFunc(mouse);
+ glutPassiveMotionFunc(drag);
+ glutIdleFunc(Idle);
+ Init();
+ glutMainLoop();
+ return 0;
+}
+
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