diff options
Diffstat (limited to 'progs/glsl/deriv.c')
| -rw-r--r-- | progs/glsl/deriv.c | 319 |
1 files changed, 319 insertions, 0 deletions
diff --git a/progs/glsl/deriv.c b/progs/glsl/deriv.c new file mode 100644 index 00000000000..8b652bc1e46 --- /dev/null +++ b/progs/glsl/deriv.c @@ -0,0 +1,319 @@ +/** + * Test OpenGL 2.0 dx/dy functions for texcoords. + * Brian Paul + * 2 May 2007 + * + * NOTE: resize the window to observe how the partial derivatives of + * the texcoords change. + */ + + +#include <assert.h> +#include <string.h> +#include <stdio.h> +#include <stdlib.h> +#include <math.h> +#include <GL/gl.h> +#include <GL/glut.h> +#include <GL/glext.h> +#include "extfuncs.h" + + +static char *FragProgFile = NULL; +static char *VertProgFile = NULL; +static GLuint fragShader; +static GLuint vertShader; +static GLuint program; +static GLuint SphereList, RectList, CurList; +static GLint win = 0; +static GLboolean anim = GL_TRUE; +static GLfloat xRot = 0.0f, yRot = 0.0f; + + +static void +Redisplay(void) +{ + glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); + + glPushMatrix(); + glRotatef(xRot, 1.0f, 0.0f, 0.0f); + glRotatef(yRot, 0.0f, 1.0f, 0.0f); + glCallList(CurList); + glPopMatrix(); + + glutSwapBuffers(); +} + + +static void +Idle(void) +{ + yRot = glutGet(GLUT_ELAPSED_TIME) * 0.1; + glutPostRedisplay(); +} + + +static void +Reshape(int width, int height) +{ + glViewport(0, 0, width, height); + glMatrixMode(GL_PROJECTION); + glLoadIdentity(); + glFrustum(-1.0, 1.0, -1.0, 1.0, 5.0, 25.0); + glMatrixMode(GL_MODELVIEW); + glLoadIdentity(); + glTranslatef(0.0f, 0.0f, -15.0f); +} + + +static void +CleanUp(void) +{ + glDeleteShader_func(fragShader); + glDeleteShader_func(vertShader); + glDeleteProgram_func(program); + glutDestroyWindow(win); +} + + +static void +Key(unsigned char key, int x, int y) +{ + (void) x; + (void) y; + + switch(key) { + case ' ': + case 'a': + anim = !anim; + if (anim) + glutIdleFunc(Idle); + else + glutIdleFunc(NULL); + break; + case 'o': + if (CurList == SphereList) + CurList = RectList; + else + CurList = SphereList; + break; + case 27: + CleanUp(); + exit(0); + break; + } + glutPostRedisplay(); +} + + +static void +SpecialKey(int key, int x, int y) +{ + const GLfloat step = 3.0f; + + (void) x; + (void) y; + + switch(key) { + case GLUT_KEY_UP: + xRot -= step; + break; + case GLUT_KEY_DOWN: + xRot += step; + break; + case GLUT_KEY_LEFT: + yRot -= step; + break; + case GLUT_KEY_RIGHT: + yRot += step; + break; + } + glutPostRedisplay(); +} + + +static void +MakeSphere(void) +{ + GLUquadricObj *obj = gluNewQuadric(); + SphereList = glGenLists(1); + gluQuadricTexture(obj, GL_TRUE); + glNewList(SphereList, GL_COMPILE); + gluSphere(obj, 2.0f, 30, 15); + glEndList(); +} + + +static void +MakeRect(void) +{ + RectList = glGenLists(1); + glNewList(RectList, GL_COMPILE); + glBegin(GL_POLYGON); + glTexCoord2f(0, 0); glVertex2f(-2, -2); + glTexCoord2f(1, 0); glVertex2f( 2, -2); + glTexCoord2f(1, 1); glVertex2f( 2, 2); + glTexCoord2f(0, 1); glVertex2f(-2, 2); + glEnd(); + glEndList(); +} + + + +static void +LoadAndCompileShader(GLuint shader, const char *text) +{ + GLint stat; + + glShaderSource_func(shader, 1, (const GLchar **) &text, NULL); + + glCompileShader_func(shader); + + glGetShaderiv_func(shader, GL_COMPILE_STATUS, &stat); + if (!stat) { + GLchar log[1000]; + GLsizei len; + glGetShaderInfoLog_func(shader, 1000, &len, log); + fprintf(stderr, "fslight: problem compiling shader:\n%s\n", log); + exit(1); + } +} + + +/** + * Read a shader from a file. + */ +static void +ReadShader(GLuint shader, const char *filename) +{ + const int max = 100*1000; + int n; + char *buffer = (char*) malloc(max); + FILE *f = fopen(filename, "r"); + if (!f) { + fprintf(stderr, "fslight: Unable to open shader file %s\n", filename); + exit(1); + } + + n = fread(buffer, 1, max, f); + printf("fslight: read %d bytes from shader file %s\n", n, filename); + if (n > 0) { + buffer[n] = 0; + LoadAndCompileShader(shader, buffer); + } + + fclose(f); + free(buffer); +} + + +static void +CheckLink(GLuint prog) +{ + GLint stat; + glGetProgramiv_func(prog, GL_LINK_STATUS, &stat); + if (!stat) { + GLchar log[1000]; + GLsizei len; + glGetProgramInfoLog_func(prog, 1000, &len, log); + fprintf(stderr, "Linker error:\n%s\n", log); + } +} + + +static void +Init(void) +{ + static const char *fragShaderText = + "void main() {\n" + " gl_FragColor = abs(dFdy(gl_TexCoord[0])) * 50.0;\n" + " // gl_FragColor = gl_TexCoord[0];\n" + "}\n"; + static const char *vertShaderText = + "void main() {\n" + " gl_Position = gl_ModelViewProjectionMatrix * gl_Vertex;\n" + " gl_TexCoord[0] = gl_MultiTexCoord0;\n" + "}\n"; + const char *version; + + version = (const char *) glGetString(GL_VERSION); + if (version[0] != '2' || version[1] != '.') { + printf("This program requires OpenGL 2.x, found %s\n", version); + exit(1); + } + + GetExtensionFuncs(); + + fragShader = glCreateShader_func(GL_FRAGMENT_SHADER); + if (FragProgFile) + ReadShader(fragShader, FragProgFile); + else + LoadAndCompileShader(fragShader, fragShaderText); + + vertShader = glCreateShader_func(GL_VERTEX_SHADER); + if (VertProgFile) + ReadShader(vertShader, VertProgFile); + else + LoadAndCompileShader(vertShader, vertShaderText); + + program = glCreateProgram_func(); + glAttachShader_func(program, fragShader); + glAttachShader_func(program, vertShader); + glLinkProgram_func(program); + CheckLink(program); + glUseProgram_func(program); + + /*assert(glGetError() == 0);*/ + + glClearColor(0.3f, 0.3f, 0.3f, 0.0f); + glEnable(GL_DEPTH_TEST); + + MakeSphere(); + MakeRect(); + + CurList = SphereList; + + printf("GL_RENDERER = %s\n",(const char *) glGetString(GL_RENDERER)); + + assert(glIsProgram_func(program)); + assert(glIsShader_func(fragShader)); + assert(glIsShader_func(vertShader)); + + glColor3f(1, 0, 0); +} + + +static void +ParseOptions(int argc, char *argv[]) +{ + int i; + for (i = 1; i < argc; i++) { + if (strcmp(argv[i], "-fs") == 0) { + FragProgFile = argv[i+1]; + } + else if (strcmp(argv[i], "-vs") == 0) { + VertProgFile = argv[i+1]; + } + } +} + + +int +main(int argc, char *argv[]) +{ + glutInit(&argc, argv); + glutInitWindowPosition( 0, 0); + glutInitWindowSize(200, 200); + glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH); + win = glutCreateWindow(argv[0]); + glutReshapeFunc(Reshape); + glutKeyboardFunc(Key); + glutSpecialFunc(SpecialKey); + glutDisplayFunc(Redisplay); + if (anim) + glutIdleFunc(Idle); + ParseOptions(argc, argv); + Init(); + glutMainLoop(); + return 0; +} |