+++ /dev/null
-/**
- * Demonstration of doing triangle rasterization with a fragment program.
- * Basic idea:
- * 1. Draw screen-aligned quad / bounding box around the triangle verts.
- * 2. For each pixel in the quad, determine if pixel is inside/outside
- * the triangle edges.
- *
- * Brian Paul
- * 1 Aug 2007
- */
-
-
-#include <assert.h>
-#include <string.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <math.h>
-#include <GL/glew.h>
-#include <GL/glut.h>
-#include "shaderutil.h"
-
-
-static GLint WinWidth = 300, WinHeight = 300;
-static char *FragProgFile = NULL;
-static char *VertProgFile = NULL;
-static GLuint fragShader;
-static GLuint vertShader;
-static GLuint program;
-static GLint win = 0;
-static GLboolean anim = GL_TRUE;
-static GLfloat Zrot = 0.0f;
-static GLint uv0, uv1, uv2;
-
-
-static const GLfloat TriVerts[3][2] = {
- { 50, 50 },
- { 250, 50 },
- { 150, 250 }
-};
-
-
-static void
-RotateVerts(GLfloat a,
- GLuint n, const GLfloat vertsIn[][2], GLfloat vertsOut[][2])
-{
- GLuint i;
- GLfloat cx = WinWidth / 2, cy = WinHeight / 2;
- for (i = 0; i < n; i++) {
- float x = vertsIn[i][0] - cx;
- float y = vertsIn[i][1] - cy;
-
- vertsOut[i][0] = x * cos(a) + y * sin(a) + cx;
- vertsOut[i][1] = -x * sin(a) + y * cos(a) + cy;
- }
-}
-
-static void
-ComputeBounds(GLuint n, GLfloat vertsIn[][2],
- GLfloat *xmin, GLfloat *ymin,
- GLfloat *xmax, GLfloat *ymax)
-{
- GLuint i;
- *xmin = *xmax = vertsIn[0][0];
- *ymin = *ymax = vertsIn[0][1];
- for (i = 1; i < n; i++) {
- if (vertsIn[i][0] < *xmin)
- *xmin = vertsIn[i][0];
- else if (vertsIn[i][0] > *xmax)
- *xmax = vertsIn[i][0];
- if (vertsIn[i][1] < *ymin)
- *ymin = vertsIn[i][1];
- else if (vertsIn[i][1] > *ymax)
- *ymax = vertsIn[i][1];
- }
-}
-
-
-static void
-Redisplay(void)
-{
- GLfloat v[3][2], xmin, ymin, xmax, ymax;
-
- RotateVerts(Zrot, 3, TriVerts, v);
- ComputeBounds(3, v, &xmin, &ymin, &xmax, &ymax);
-
- glUniform2fv(uv0, 1, v[0]);
- glUniform2fv(uv1, 1, v[1]);
- glUniform2fv(uv2, 1, v[2]);
-
- glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
-
- glPushMatrix();
- glBegin(GL_POLYGON);
- glVertex2f(xmin, ymin);
- glVertex2f(xmax, ymin);
- glVertex2f(xmax, ymax);
- glVertex2f(xmin, ymax);
- glEnd();
- glPopMatrix();
-
- glutSwapBuffers();
-}
-
-
-static void
-Idle(void)
-{
- if (anim) {
- Zrot = glutGet(GLUT_ELAPSED_TIME) * 0.0005;
- glutPostRedisplay();
- }
- else
- abort();
-}
-
-
-static void
-Reshape(int width, int height)
-{
- glViewport(0, 0, width, height);
- glMatrixMode(GL_PROJECTION);
- glLoadIdentity();
- glOrtho(0, width, 0, height, -1, 1);
-
- glMatrixMode(GL_MODELVIEW);
- glLoadIdentity();
-}
-
-
-static void
-CleanUp(void)
-{
- glDeleteShader(fragShader);
- glDeleteShader(vertShader);
- glDeleteProgram(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 'z':
- Zrot = 0;
- break;
- case 's':
- Zrot += 0.05;
- break;
- case 27:
- CleanUp();
- exit(0);
- break;
- }
- glutPostRedisplay();
-}
-
-
-static void
-Init(void)
-{
- static const char *fragShaderText =
- "uniform vec2 v0, v1, v2; \n"
- "float crs(const vec2 u, const vec2 v) \n"
- "{ \n"
- " return u.x * v.y - u.y * v.x; \n"
- "} \n"
- "\n"
- "void main() {\n"
- " vec2 p = gl_FragCoord.xy; \n"
- " if (crs(v1 - v0, p - v0) >= 0.0 && \n"
- " crs(v2 - v1, p - v1) >= 0.0 && \n"
- " crs(v0 - v2, p - v2) >= 0.0) \n"
- " gl_FragColor = vec4(1.0); \n"
- " else \n"
- " gl_FragColor = vec4(0.5); \n"
- "}\n";
- static const char *vertShaderText =
- "void main() {\n"
- " gl_Position = ftransform(); \n"
- "}\n";
-
- if (!ShadersSupported())
- exit(1);
-
- vertShader = CompileShaderText(GL_VERTEX_SHADER, vertShaderText);
- fragShader = CompileShaderText(GL_FRAGMENT_SHADER, fragShaderText);
- program = LinkShaders(vertShader, fragShader);
-
- glUseProgram(program);
-
- uv0 = glGetUniformLocation(program, "v0");
- uv1 = glGetUniformLocation(program, "v1");
- uv2 = glGetUniformLocation(program, "v2");
- printf("Uniforms: %d %d %d\n", uv0, uv1, uv2);
-
- /*assert(glGetError() == 0);*/
-
- glClearColor(0.3f, 0.3f, 0.3f, 0.0f);
- glEnable(GL_DEPTH_TEST);
-
- printf("GL_RENDERER = %s\n",(const char *) glGetString(GL_RENDERER));
-
- assert(glIsProgram(program));
- assert(glIsShader(fragShader));
- assert(glIsShader(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);
- glutInitWindowSize(WinWidth, WinHeight);
- glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);
- win = glutCreateWindow(argv[0]);
- glewInit();
- glutReshapeFunc(Reshape);
- glutKeyboardFunc(Key);
- glutDisplayFunc(Redisplay);
- if (anim)
- glutIdleFunc(Idle);
- ParseOptions(argc, argv);
- Init();
- glutMainLoop();
- return 0;
-}
projects / mesa.git / blobdiff