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-rw-r--r--progs/vpglsl/vp-tris.c313
1 files changed, 313 insertions, 0 deletions
diff --git a/progs/vpglsl/vp-tris.c b/progs/vpglsl/vp-tris.c
new file mode 100644
index 0000000000..9108d3f197
--- /dev/null
+++ b/progs/vpglsl/vp-tris.c
@@ -0,0 +1,313 @@
+
+#include <assert.h>
+#include <string.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <math.h>
+#define GL_GLEXT_PROTOTYPES
+#include <GL/glut.h>
+
+static const char *filename = NULL;
+static GLuint nr_steps = 4;
+
+static GLuint fragShader;
+static GLuint vertShader;
+static GLuint program;
+
+static void usage( char *name )
+{
+ fprintf( stderr, "usage: %s [ options ] shader_filename\n", name );
+ fprintf( stderr, "\n" );
+ fprintf( stderr, "options:\n" );
+ fprintf( stderr, " -f flat shaded\n" );
+ fprintf( stderr, " -nNr subdivision steps\n" );
+}
+
+
+static void load_and_compile_shader(GLuint shader, const char *text)
+{
+ GLint stat;
+
+ glShaderSource(shader, 1, (const GLchar **) &text, NULL);
+
+ glCompileShader(shader);
+
+ glGetShaderiv(shader, GL_COMPILE_STATUS, &stat);
+ if (!stat) {
+ GLchar log[1000];
+ GLsizei len;
+ glGetShaderInfoLog(shader, 1000, &len, log);
+ fprintf(stderr, "vp-tris: problem compiling shader:\n%s\n", log);
+ exit(1);
+ }
+}
+
+static void read_shader(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, "vp-tris: Unable to open shader file %s\n", filename);
+ exit(1);
+ }
+
+ n = fread(buffer, 1, max, f);
+ printf("vp-tris: read %d bytes from shader file %s\n", n, filename);
+ if (n > 0) {
+ buffer[n] = 0;
+ load_and_compile_shader(shader, buffer);
+ }
+
+ fclose(f);
+ free(buffer);
+}
+
+static void check_link(GLuint prog)
+{
+ GLint stat;
+ glGetProgramiv(prog, GL_LINK_STATUS, &stat);
+ if (!stat) {
+ GLchar log[1000];
+ GLsizei len;
+ glGetProgramInfoLog(prog, 1000, &len, log);
+ fprintf(stderr, "Linker error:\n%s\n", log);
+ }
+}
+
+static void setup_uniforms()
+{
+ {
+ GLuint loc1f = glGetUniformLocationARB(program, "Offset1f");
+ GLuint loc2f = glGetUniformLocationARB(program, "Offset2f");
+ GLuint loc4f = glGetUniformLocationARB(program, "Offset4f");
+ GLfloat vecKer[] =
+ { 1.0, 0.0, 0.0, 1.0,
+ 0.0, 1.0, 0.0, 1.0,
+ 1.0, 0.0, 0.0, 1.0,
+ 0.0, 0.0, 0.0, 1.0
+ };
+ if (loc1f >= 0)
+ glUniform1fv(loc1f, 16, vecKer);
+
+ if (loc2f >= 0)
+ glUniform2fv(loc2f, 8, vecKer);
+
+ if (loc4f >= 0)
+ glUniform4fv(loc4f, 4, vecKer);
+
+ }
+
+ GLuint loc1f = glGetUniformLocationARB(program, "KernelValue1f");
+ GLuint loc2f = glGetUniformLocationARB(program, "KernelValue2f");
+ GLuint loc4f = glGetUniformLocationARB(program, "KernelValue4f");
+ GLfloat vecKer[] =
+ { 1.0, 0.0, 0.0, 0.25,
+ 0.0, 1.0, 0.0, 0.25,
+ 0.0, 0.0, 1.0, 0.25,
+ 0.0, 0.0, 0.0, 0.25,
+ 0.5, 0.0, 0.0, 0.35,
+ 0.0, 0.5, 0.0, 0.35,
+ 0.0, 0.0, 0.5, 0.35,
+ 0.0, 0.0, 0.0, 0.35
+ };
+ if (loc1f >= 0)
+ glUniform1fv(loc1f, 16, vecKer);
+
+ if (loc2f >= 0)
+ glUniform2fv(loc2f, 8, vecKer);
+
+ if (loc4f >= 0)
+ glUniform4fv(loc4f, 4, vecKer);
+}
+
+static void prepare_shaders()
+{
+ static const char *fragShaderText =
+ "void main() {\n"
+ " gl_FragColor = gl_Color;\n"
+ "}\n";
+ static const char *vertShaderText =
+ "void main() {\n"
+ " gl_FrontColor = gl_Color;\n"
+ " gl_Position = gl_ModelViewProjectionMatrix * gl_Vertex;\n"
+ "}\n";
+ fragShader = glCreateShader(GL_FRAGMENT_SHADER);
+ load_and_compile_shader(fragShader, fragShaderText);
+
+
+ vertShader = glCreateShader(GL_VERTEX_SHADER);
+ if (filename)
+ read_shader(vertShader, filename);
+ else
+ load_and_compile_shader(vertShader, vertShaderText);
+
+ program = glCreateProgram();
+ glAttachShader(program, fragShader);
+ glAttachShader(program, vertShader);
+ glLinkProgram(program);
+ check_link(program);
+ glUseProgram(program);
+
+ setup_uniforms();
+}
+
+static void args(int argc, char *argv[])
+{
+ GLint i;
+
+ for (i = 1; i < argc; i++) {
+ if (strncmp(argv[i], "-n", 2) == 0) {
+ nr_steps = atoi((argv[i]) + 2);
+ }
+ else if (strcmp(argv[i], "-f") == 0) {
+ glShadeModel(GL_FLAT);
+ }
+ else if (i == argc - 1) {
+ filename = argv[i];
+ }
+ else {
+ usage(argv[0]);
+ exit(1);
+ }
+ }
+
+ if (!filename) {
+ usage(argv[0]);
+ exit(1);
+ }
+}
+
+
+
+
+union vert {
+ struct {
+ GLfloat color[3];
+ GLfloat pos[3];
+ } v;
+ GLfloat f[6];
+};
+
+static void make_midpoint( union vert *out,
+ const union vert *v0,
+ const union vert *v1)
+{
+ int i;
+ for (i = 0; i < 6; i++)
+ out->f[i] = v0->f[i] + .5 * (v1->f[i] - v0->f[i]);
+}
+
+static void subdiv( union vert *v0,
+ union vert *v1,
+ union vert *v2,
+ GLuint depth )
+{
+ if (depth == 0) {
+ glColor3fv(v0->v.color);
+ glVertex3fv(v0->v.pos);
+ glColor3fv(v1->v.color);
+ glVertex3fv(v1->v.pos);
+ glColor3fv(v2->v.color);
+ glVertex3fv(v2->v.pos);
+ }
+ else {
+ union vert m[3];
+
+ make_midpoint(&m[0], v0, v1);
+ make_midpoint(&m[1], v1, v2);
+ make_midpoint(&m[2], v2, v0);
+
+ subdiv(&m[0], &m[2], v0, depth-1);
+ subdiv(&m[1], &m[0], v1, depth-1);
+ subdiv(&m[2], &m[1], v2, depth-1);
+ subdiv(&m[0], &m[1], &m[2], depth-1);
+ }
+}
+
+/** Assignment */
+#define ASSIGN_3V( V, V0, V1, V2 ) \
+do { \
+ V[0] = V0; \
+ V[1] = V1; \
+ V[2] = V2; \
+} while(0)
+
+static void Display( void )
+{
+ glClearColor(0.3, 0.3, 0.3, 1);
+ glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
+
+ glUseProgram(program);
+
+ glBegin(GL_TRIANGLES);
+
+
+ {
+ union vert v[3];
+
+ ASSIGN_3V(v[0].v.color, 0,0,1);
+ ASSIGN_3V(v[0].v.pos, 0.9, -0.9, 0.0);
+ ASSIGN_3V(v[1].v.color, 1,0,0);
+ ASSIGN_3V(v[1].v.pos, 0.9, 0.9, 0.0);
+ ASSIGN_3V(v[2].v.color, 0,1,0);
+ ASSIGN_3V(v[2].v.pos, -0.9, 0, 0.0);
+
+ subdiv(&v[0], &v[1], &v[2], nr_steps);
+ }
+
+ glEnd();
+
+
+ glFlush();
+}
+
+
+static void Reshape( int width, int height )
+{
+ glViewport( 0, 0, width, height );
+ glMatrixMode( GL_PROJECTION );
+ glLoadIdentity();
+ glOrtho(-1.0, 1.0, -1.0, 1.0, -0.5, 1000.0);
+ glMatrixMode( GL_MODELVIEW );
+ glLoadIdentity();
+ /*glTranslatef( 0.0, 0.0, -15.0 );*/
+}
+
+
+static void CleanUp(void)
+{
+ glDeleteShader(fragShader);
+ glDeleteShader(vertShader);
+ glDeleteProgram(program);
+}
+
+static void Key( unsigned char key, int x, int y )
+{
+ (void) x;
+ (void) y;
+ switch (key) {
+ case 27:
+ CleanUp();
+ exit(0);
+ break;
+ }
+ glutPostRedisplay();
+}
+
+int main( int argc, char *argv[] )
+{
+ glutInit( &argc, argv );
+ glutInitWindowPosition( 0, 0 );
+ glutInitWindowSize( 250, 250 );
+ glutInitDisplayMode( GLUT_RGB | GLUT_SINGLE | GLUT_DEPTH );
+ glutCreateWindow(argv[0]);
+ glutReshapeFunc( Reshape );
+ glutKeyboardFunc( Key );
+ glutDisplayFunc( Display );
+ args( argc, argv );
+ prepare_shaders();
+ glutMainLoop();
+ return 0;
+}
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