glGenTextures — generate texture names
void glGenTextures( | GLsizei | n, |
GLuint * | textures) ; |
n
Specifies the number of texture names to be generated.
textures
Specifies an array in which the generated texture names are stored.
glGenTextures
returns n
texture names in textures
. There is no guarantee that the names form a contiguous set of integers; however, it is guaranteed that none of the returned names was in use immediately before the call to glGenTextures
.
The generated textures have no dimensionality; they assume the dimensionality of the texture target to which they are first bound (see glBindTexture).
Texture names returned by a call to glGenTextures
are not returned by subsequent calls, unless they are first deleted with glDeleteTextures.
// fbo_width and fbo_height are the desired width and height of the FBO. // For Opengl <= 4.4 or if the GL_ARB_texture_non_power_of_two extension // is present, fbo_width and fbo_height can be values other than 2^n for // some integer n. // Build the texture that will serve as the color attachment for the framebuffer. GLuint texture_map; glGenTextures(1, &texture_map); glBindTexture(GL_TEXTURE_2D, texture_map); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_BORDER); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_BORDER); glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, fbo_width, fbo_height, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL); glBindTexture(GL_TEXTURE_2D, 0); // Build the texture that will serve as the depth attachment for the framebuffer. GLuint depth_texture; glGenTextures(1, &depth_texture); glBindTexture(GL_TEXTURE_2D, depth_texture); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE); glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT, fbo_width, fbo_height, 0, GL_DEPTH_COMPONENT, GL_UNSIGNED_BYTE, NULL); glBindTexture(GL_TEXTURE_2D, 0); // Build the framebuffer. GLuint framebuffer; glGenFramebuffers(1, &framebuffer); glBindFramebuffer(GL_FRAMEBUFFER, (GLuint)framebuffer); glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, texture_map, 0); glFramebufferTexture2D(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_TEXTURE_2D, depth_texture, 0); GLenum status = glCheckFramebufferStatus(GL_FRAMEBUFFER); if (status != GL_FRAMEBUFFER_COMPLETE) // Error glBindFramebuffer(GL_FRAMEBUFFER, 0);
GLuint texture_id; glGenTextures(1, &texture_id); glBindTexture(GL_TEXTURE_2D, texture_id); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE); // texture_data is the source data of your texture, in this case // its size is sizeof(unsigned char) * texture_width * texture_height * 4 glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, texture_width, texture_height, 0, GL_RGBA, GL_UNSIGNED_BYTE, texture_data); glGenerateMipmap(GL_TEXTURE_2D); // Unavailable in OpenGL 2.1, use gluBuild2DMipmaps() instead glBindTexture(GL_TEXTURE_2D, 0);
open.gl - Framebuffers
opengl-tutorial.org - Tutorial 14 : Render To Texture
opengl-tutorial.org - Tutorial 16 : Shadow mapping
opengl-tutorial.org - Tutorial 5 : A Textured Cube
glBindTexture, glCopyTexImage1D, glCopyTexImage2D, glDeleteTextures, glGet, glGetTexParameter, glTexImage1D, glTexImage2D, glTexImage3D, glTexParameter
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