【glTexGen】
Rather than having to explicitly provide a texture coordinate for each vertex, we can use texture coordinate generation (texgen) functions to have OpenGL automatically compute texture coordinates.
This uses the function glTexGen, and the glEnable modes GL_TEXTURE_GEN_S & GL_TEXTURE_GEN_T.
planeCoefficients = [ 1, 0, 0, 0 ] glTexGeni(GL_S, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR) glTexGenfv(GL_S, GL_OBJECT_PLANE, planeCoefficients) glEnable(GL_TEXTURE_GEN_S) glBegin(GL_QUADS) glVertex3f(-3.25, -1, 0) glVertex3f(-1.25, -1, 0) glVertex3f(-1.25, 1, 0) glVertex3f(-3.25, 1, 0) glEnd()
【API说明】
coord：Specifies a texture coordinate. Must be one of GL_S, GL_T, GL_R, or GL_Q.
pname：Specifies the symbolic name of the texture-coordinate generation function. Must be GL_TEXTURE_GEN_MODE.
param：Specifies a single-valued texture generation parameter, one of GL_OBJECT_LINEAR, GL_EYE_LINEAR, GL_SPHERE_MAP, GL_NORMAL_MAP, or GL_REFLECTION_MAP.
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