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//========================================================================
// This is an example program for the GLFW library
//
// It shows texture loading with mipmap generation and rendering with
// trilienar texture filtering
//========================================================================
#include <stdio.h>
#include <stdlib.h>
#include <GL/glfw.h>
#ifdef EMSCRIPTEN
#include <emscripten/emscripten.h>
#endif
int width, height, x;
double time;
GLboolean running;
void iteration(){
// Get time and mouse position
time = glfwGetTime();
glfwGetMousePos( &x, NULL );
// Get window size (may be different than the requested size)
glfwGetWindowSize( &width, &height );
height = height > 0 ? height : 1;
// Set viewport
glViewport( 0, 0, width, height );
// Clear color buffer
glClearColor( 0.0f, 0.0f, 0.0f, 0.0f);
glClear( GL_COLOR_BUFFER_BIT );
// Select and setup the projection matrix
glMatrixMode( GL_PROJECTION );
glLoadIdentity();
gluPerspective( 65.0f, (GLfloat)width / (GLfloat)height, 1.0f,
50.0f );
// Select and setup the modelview matrix
glMatrixMode( GL_MODELVIEW );
glLoadIdentity();
gluLookAt( 0.0f, 3.0f, -20.0f, // Eye-position
0.0f, -4.0f, -11.0f, // View-point
0.0f, 1.0f, 0.0f ); // Up-vector
// Draw a textured quad
glRotatef( 0.05f * (GLfloat)x + (GLfloat)time * 5.0f, 0.0f, 1.0f, 0.0f );
glBegin( GL_QUADS );
glTexCoord2f( -20.0f, 20.0f );
glVertex3f( -50.0f, 0.0f, -50.0f );
glTexCoord2f( 20.0f, 20.0f );
glVertex3f( 50.0f, 0.0f, -50.0f );
glTexCoord2f( 20.0f, -20.0f );
glVertex3f( 50.0f, 0.0f, 50.0f );
glTexCoord2f( -20.0f, -20.0f );
glVertex3f( -50.0f, 0.0f, 50.0f );
glEnd();
// Swap buffers
glfwSwapBuffers();
// Check if the ESC key was pressed or the window was closed
running = !glfwGetKey( GLFW_KEY_ESC ) &&
glfwGetWindowParam( GLFW_OPENED );
}
int main( void )
{
GLuint textureID;
char* texturePath = "mipmaps.tga";
// Initialise GLFW
if( !glfwInit() )
{
fprintf( stderr, "Failed to initialize GLFW\n" );
exit( EXIT_FAILURE );
}
// Open OpenGL window
if( !glfwOpenWindow( 640, 480, 0,0,0,0, 0,0, GLFW_WINDOW ) )
{
fprintf( stderr, "Failed to open GLFW window\n" );
glfwTerminate();
exit( EXIT_FAILURE );
}
glfwSetWindowTitle( "Trilinear interpolation" );
// Enable sticky keys
glfwEnable( GLFW_STICKY_KEYS );
// Enable vertical sync (on cards that support it)
glfwSwapInterval( 1 );
// Generate and bind our texture ID
glGenTextures( 1, &textureID );
glBindTexture( GL_TEXTURE_2D, textureID );
// Load texture from file into video memory, including mipmap levels
if( !glfwLoadTexture2D( texturePath, GLFW_BUILD_MIPMAPS_BIT ) )
{
fprintf( stderr, "Failed to load texture %s\n", texturePath );
glfwTerminate();
exit( EXIT_FAILURE );
}
// Use trilinear interpolation (GL_LINEAR_MIPMAP_LINEAR)
glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER,
GL_LINEAR_MIPMAP_LINEAR );
glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER,
GL_LINEAR );
// Enable plain 2D texturing
glEnable( GL_TEXTURE_2D );
running = GL_TRUE;
#ifdef EMSCRIPTEN
emscripten_set_main_loop (iteration, 0, 1);
#else
// Main loop
while( running )
{
iteration();
}
#endif
// Close OpenGL window and terminate GLFW
glfwTerminate();
exit( EXIT_SUCCESS );
}
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