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/**
* Test very basic glsl functionality (identity vertex and fragment shaders).
* Brian Paul & Stephane Marchesin
*/
#include <assert.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <glad/glad.h>
#include "glut_wrap.h"
#include "shaderutil.h"
static GLuint fragShader;
static GLuint vertShader;
static GLuint program;
static GLint win = 0;
static void
Redisplay(void)
{
glClear(GL_COLOR_BUFFER_BIT);
glBegin(GL_TRIANGLES);
glVertex3f(-0.9, -0.9, 0.0);
glVertex3f( 0.9, -0.9, 0.0);
glVertex3f( 0.0, 0.9, 0.0);
glEnd();
glutSwapBuffers();
}
static void
Reshape(int width, int height)
{
glViewport(0, 0, width, height);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
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)
{
if (key == 27) {
CleanUp();
exit(0);
}
glutPostRedisplay();
}
static void
Init(void)
{
static const char *fragShaderText =
"void main() {\n"
" gl_FragColor = vec4(1.0,0.0,0.0,1.0);\n"
"}\n";
static const char *vertShaderText =
"void main() {\n"
" gl_Position = gl_Vertex;\n"
"}\n";
if (!ShadersSupported())
exit(1);
fragShader = CompileShaderText(GL_FRAGMENT_SHADER, fragShaderText);
vertShader = CompileShaderText(GL_VERTEX_SHADER, vertShaderText);
program = LinkShaders(vertShader, fragShader);
glUseProgram(program);
assert(glGetError() == 0);
glClearColor(0.3f, 0.3f, 0.3f, 1.0f);
printf("GL_RENDERER = %s\n",(const char *) glGetString(GL_RENDERER));
assert(glIsProgram(program));
assert(glIsShader(fragShader));
assert(glIsShader(vertShader));
glColor3f(1, 0, 0);
}
int
main(int argc, char *argv[])
{
glutInit(&argc, argv);
glutInitWindowSize(200, 200);
glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE);
win = glutCreateWindow(argv[0]);
gladLoadGL();
glutReshapeFunc(Reshape);
glutKeyboardFunc(Key);
glutDisplayFunc(Redisplay);
Init();
glutMainLoop();
return 0;
}
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