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OpenGL (1.2 - 2.0) Code Samples - Page 3
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Texture
Addressing |
| Demonstrates how texture addressing
works under OpenGL by allowing the texture
addressing mode to be changed at run-time
with a textured quad whose texture coordinates
range from 0.0 to 3.0. A few of the modes
are available through extensions. The sample
uses the following extensions:
ARB_texture_mirrored_repeat,
ARB_texture_border_clamp,
SGIS_texture_edge_clamp. Check out
the DirectX9 source
code page for the Direct3D equivalent of
this sample.
Relevant Keywords: auxDIBImageLoad,
glGenTextures, glBindTexture, glTexParameteri,
glTexImage2D, glEnable, glBindTexture, AUX_RGBImageRec,
GL_T2F_V3F, GL_TEXTURE_WRAP_S, GL_TEXTURE_WRAP_T,
GL_REPEAT, GL_CLAMP, GL_MIRRORED_REPEAT_ARB,
GL_CLAMP_TO_BORDER_ARB, GL_CLAMP_TO_EDGE,
GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_TEXTURE_MAG_FILTER,
GL_LINEAR, and GL_UNSIGNED_BYTE.
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Texture
Sub-loading |
| Demonstrates how texture sub-loading
works under OpenGL by copying a smaller
texture over the texel data of a larger
texture. Check out the
DirectX9 source
code page for the Direct3D equivalent of
this sample.
Relevant Keywords: glTexSubImage2D,
auxDIBImageLoad, glGenTextures, glBindTexture,
glTexParameteri, glTexImage2D, glEnable,
glBindTexture, AUX_RGBImageRec, GL_T2F_V3F,
GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_TEXTURE_MAG_FILTER,
GL_LINEAR, and GL_UNSIGNED_BYTE.
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Texture
Mip-mapping |
| This sample demonstrates how
mip-mapping works under OpenGL by tiling
a single textured quad across a 25x25 unit
area. The original texture is simply white
with a thin black border, but in a effort
to show mip-mapping in action, several mip-map
levels have been altered by replacing the
auto generated mip-map texture for that
level with a color-coded version. This causes
mip-map filtering to produce rainbow colored
bands which radiate across the surface as
the eye point moves about. Check out the
DirectX9 source
code page for the Direct3D equivalent of
this sample.
Relevant Keywords: gluBuild2DMipmaps,
glPixelStorei, auxDIBImageLoad, glGenTextures,
glBindTexture, glTexParameteri, glTexImage2D,
glEnable, glBindTexture, AUX_RGBImageRec,
GL_UNPACK_ALIGNMENT, GL_T2F_V3F, GL_TEXTURE_2D,
GL_TEXTURE_MIN_FILTER, GL_TEXTURE_MAG_FILTER,
GL_NEAREST, GL_LINEAR, GL_NEAREST_MIPMAP_NEAREST,
GL_LINEAR_MIPMAP_NEAREST, GL_NEAREST_MIPMAP_LINEAR,
GL_LINEAR_MIPMAP_LINEAR, and GL_UNSIGNED_BYTE.
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Multi-Texturing |
| This sample demonstrates how
to perform multi-texturing with OpenGL's
ARB_multitexture extension by either
modulating or adding two textures together
in one rendering pass. Check out the
DirectX9 source
code page for the Direct3D equivalent of
this sample.
Relevant Keywords: GL_ARB_multitexture,
glActiveTextureARB, glMultiTexCoord2fARB,
glClientActiveTextureARB, glTexEnvi, glVertex3f,
wglGetProcAddress, glGetString, auxDIBImageLoad,
glGenTextures, glBindTexture, glTexParameteri,
glTexImage2D, glEnable, glDisable, glBindTexture,
AUX_RGBImageRec, GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE,
GL_MODULATE, GL_ADD, GL_TEXTURE0_ARB, GL_TEXTURE1_ARB,
GL_EXTENSIONS, GL_BLEND, GL_TEXTURE_2D,
GL_TEXTURE_MIN_FILTER, GL_TEXTURE_MAG_FILTER,
GL_LINEAR, GL_UNSIGNED_BYTE, PFNGLACTIVETEXTUREARBPROC,
PFNGLMULTITEXCOORD2FARBPROC, and PFNGLCLIENTACTIVETEXTUREARBPROC.
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Alpha
Texture Blending
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This sample demonstrates how to perform
alpha blending using the alpha channel of
a standard .tga texture. For proper alpha
blending, the sample uses a cull-mode sorting
trick to ensure the sides of the textured
cube get rendered in back-to-front order.
Check out the DirectX9
source code page for the Direct3D equivalent
of this sample.
Relevant Keywords: glGenTextures,
glBindTexture, glTexParameteri, glTexImage2D,
glEnable, glDisable, GL_T2F_V3F, GL_DEPTH_TEST,
GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_TEXTURE_MAG_FILTER,
GL_BLEND, GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA,
GL_LINEAR, GL_CULL_FACE, GL_FRONT, GL_BACK,
and GL_UNSIGNED_BYTE.
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