I’ve read NeHe’s tutorail on texture mapping… and I wish to show a bmp in a window (640x400) everything works fine and the image displays when its small (256x256) but when i attempt to display it whilst its large (using below code) It just shows up as white!
glBindTexture(GL_TEXTURE_2D, texture[0]); // Select Our Logo Texture
glBegin(GL_QUADS); // Start Drawing A Textured Quad
glTexCoord2f(0.0f, -roll+0.0f); glVertex3f(-1.1f, -1.1f, 0.0f); // Bottom Left
glTexCoord2f(3.0f, -roll+0.0f); glVertex3f( 1.1f, -1.1f, 0.0f); // Bottom Right
glTexCoord2f(3.0f, -roll+3.0f); glVertex3f( 1.1f, 1.1f, 0.0f); // Top Right
glTexCoord2f(0.0f, -roll+3.0f); glVertex3f(-1.1f, 1.1f, 0.0f); // Top Left
glEnd();
Are you using two diffrent sized images, one for the windowed and one for the full screen?
Originally posted by Nial:
[b]I’ve read NeHe’s tutorail on texture mapping… and I wish to show a bmp in a window (640x400) everything works fine and the image displays when its small (256x256) but when i attempt to display it whilst its large (using below code) It just shows up as white!
glBindTexture(GL_TEXTURE_2D, texture[0]); // Select Our Logo Texture
glBegin(GL_QUADS); // Start Drawing A Textured Quad
glTexCoord2f(0.0f, -roll+0.0f); glVertex3f(-1.1f, -1.1f, 0.0f); // Bottom Left
glTexCoord2f(3.0f, -roll+0.0f); glVertex3f( 1.1f, -1.1f, 0.0f); // Bottom Right
glTexCoord2f(3.0f, -roll+3.0f); glVertex3f( 1.1f, 1.1f, 0.0f); // Top Right
glTexCoord2f(0.0f, -roll+3.0f); glVertex3f(-1.1f, 1.1f, 0.0f); // Top Left
glEnd();[/b]
So you changed the size of the image? It needs to be a power of two from my understanding, you can prolly bypass. But for what your doing, I’d make it a power of 2. IE:
But it shows 9 smaller version in the window. Its got the polygon the width and height of the screen but its not applying the image actual size heres my drawglscene code:
int DrawGLScene(GLvoid) // Here’s Where We Do All The Drawing
{
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); // Clear The Screen And The Depth Buffer
glLoadIdentity(); // Reset The Modelview Matrix
glTranslatef(0.0f,0.0f,-2.0f); // Move Into The Screen 5 Units
glPolygonMode(GL_FRONT_AND_BACK,GL_FILL);
glBindTexture(GL_TEXTURE_2D, texture[0]); // Select Our Logo Texture
glBegin(GL_QUADS); // Start Drawing A Textured Quad
glTexCoord2f(0.0f, -roll+0.0f); glVertex3f(-1.1f, -1.1f, 0.0f); // Bottom Left
glTexCoord2f(3.0f, -roll+0.0f); glVertex3f( 1.1f, -1.1f, 0.0f); // Bottom Right
glTexCoord2f(3.0f, -roll+3.0f); glVertex3f( 1.1f, 1.1f, 0.0f); // Top Right
glTexCoord2f(0.0f, -roll+3.0f); glVertex3f(-1.1f, 1.1f, 0.0f); // Top Left
glEnd(); // Done Drawing The Quad
glEnable(GL_BLEND); // Enable Blending
glDisable(GL_DEPTH_TEST); // Disable Depth Testing
if (masking) // Is Masking Enabled?
{
glBlendFunc(GL_DST_COLOR,GL_ZERO); // Blend Screen Color With Zero (Black)
}
glEnable(GL_DEPTH_TEST); // Enable Depth Testing
glDisable(GL_BLEND); // Disable Blending
return TRUE; // Everything Went OK
Ya, I forgot to mention, change the “3” in all of the glTexCoord to 1. What it does when set to 3 is devide the Face into a 3x3 Square. (9 Seperate sections) and maps the texture to each individual sections.
Keep in mind though, if you come across making a large wall, increasing this number can be helpful to add detail, etc.
IE:
glTexCoord2f(1.0f, -roll);
Originally posted by Nial:
[b]Okay 512x512, the image works!
But it shows 9 smaller version in the window. Its got the polygon the width and height of the screen but its not applying the image actual size heres my drawglscene code:
int DrawGLScene(GLvoid) // Here’s Where We Do All The Drawing
{
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); // Clear The Screen And The Depth Buffer
glLoadIdentity(); // Reset The Modelview Matrix
glTranslatef(0.0f,0.0f,-2.0f); // Move Into The Screen 5 Units
glPolygonMode(GL_FRONT_AND_BACK,GL_FILL);
glBindTexture(GL_TEXTURE_2D, texture[0]); // Select Our Logo Texture
glBegin(GL_QUADS); // Start Drawing A Textured Quad
glTexCoord2f(0.0f, -roll+0.0f); glVertex3f(-1.1f, -1.1f, 0.0f); // Bottom Left
glTexCoord2f(3.0f, -roll+0.0f); glVertex3f( 1.1f, -1.1f, 0.0f); // Bottom Right
glTexCoord2f(3.0f, -roll+3.0f); glVertex3f( 1.1f, 1.1f, 0.0f); // Top Right
glTexCoord2f(0.0f, -roll+3.0f); glVertex3f(-1.1f, 1.1f, 0.0f); // Top Left
glEnd(); // Done Drawing The Quad