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glTexImage2D

Name

glTexImage2D — specify a two-dimensional texture image

C Specification

void glTexImage2D( GLenum target,
  GLint level,
  GLint internalFormat,
  GLsizei width,
  GLsizei height,
  GLint border,
  GLenum format,
  GLenum type,
  const GLvoid * data);
 

Parameters

target

Specifies the target texture. Must be GL_TEXTURE_2D, GL_TEXTURE_CUBE_MAP_POSITIVE_X, GL_TEXTURE_CUBE_MAP_NEGATIVE_X, GL_TEXTURE_CUBE_MAP_POSITIVE_Y, GL_TEXTURE_CUBE_MAP_NEGATIVE_Y, GL_TEXTURE_CUBE_MAP_POSITIVE_Z, or GL_TEXTURE_CUBE_MAP_NEGATIVE_Z.

level

Specifies the level-of-detail number. Level 0 is the base image level. Level n is the nth mipmap reduction image.

internalFormat

Specifies the number of color components in the texture. Must be one of base internal formats given in Table 1, or one of the sized internal formats given in Table 2, below.

width

Specifies the width of the texture image. All implementations support texture images that are at least 2048 texels wide.

height

Specifies the height of the texture image. All implementations support texture images that are at least 2048 texels high.

border

This value must be 0.

format

Specifies the format of the pixel data. The following symbolic values are accepted: GL_RED, GL_RED_INTEGER, GL_RG, GL_RG_INTEGER, GL_RGB, GL_RGB_INTEGER, GL_RGBA, GL_RGBA_INTEGER, GL_DEPTH_COMPONENT, GL_DEPTH_STENCIL, GL_LUMINANCE_ALPHA, GL_LUMINANCE, and GL_ALPHA.

type

Specifies the data type of the pixel data. The following symbolic values are accepted: GL_UNSIGNED_BYTE, GL_BYTE, GL_UNSIGNED_SHORT, GL_SHORT, GL_UNSIGNED_INT, GL_INT, GL_HALF_FLOAT, GL_FLOAT, GL_UNSIGNED_SHORT_5_6_5, GL_UNSIGNED_SHORT_4_4_4_4, GL_UNSIGNED_SHORT_5_5_5_1, GL_UNSIGNED_INT_2_10_10_10_REV, GL_UNSIGNED_INT_10F_11F_11F_REV, GL_UNSIGNED_INT_5_9_9_9_REV, GL_UNSIGNED_INT_24_8, and GL_FLOAT_32_UNSIGNED_INT_24_8_REV.

data

Specifies a pointer to the image data in memory.

Description

Texturing allows elements of an image array to be read by shaders.

To define texture images, call glTexImage2D. The arguments describe the parameters of the texture image, such as height, width, width of the border, level-of-detail number (see glTexParameter), and number of color components provided. The last three arguments describe how the image is represented in memory.

If target is GL_TEXTURE_2D or one of the GL_TEXTURE_CUBE_MAP targets, data is read from data as a sequence of signed or unsigned bytes, shorts, or longs, or single-precision floating-point values, depending on type. These values are grouped into sets of one, two, three, or four values, depending on format, to form elements.

If a non-zero named buffer object is bound to the GL_PIXEL_UNPACK_BUFFER target (see glBindBuffer) while a texture image is specified, data is treated as a byte offset into the buffer object's data store.

The first element corresponds to the lower left corner of the texture image. Subsequent elements progress left-to-right through the remaining texels in the lowest row of the texture image, and then in successively higher rows of the texture image. The final element corresponds to the upper right corner of the texture image.

format determines the composition of each element in data. It can assume one of these symbolic values:

GL_RED

Each element is a single red component. For fixed point normalized components, the GL converts it to floating point, clamps to the range [0,1], and assembles it into an RGBA element by attaching 0.0 for green and blue, and 1.0 for alpha.

GL_RED_INTEGER

Each element is a single red component. The GL performs assembles it into an RGBA element by attaching 0 for green and blue, and 1 for alpha.

GL_RG

Each element is a red/green double. For fixed point normalized components, the GL converts each component to floating point, clamps to the range [0,1], and assembles them into an RGBA element by attaching 0.0 for blue, and 1.0 for alpha.

GL_RG

Each element is a red/green double. The GL assembles them into an RGBA element by attaching 0 for blue, and 1 for alpha.

GL_RGB

Each element is an RGB triple. For fixed point normalized components, the GL converts each component to floating point, clamps to the range [0,1], and assembles them into an RGBA element by attaching 1.0 for alpha.

GL_RGB_INTEGER

Each element is an RGB triple. The GL assembles them into an RGBA element by attaching 1 for alpha.

GL_RGBA

Each element contains all four components. For fixed point normalized components, the GL converts each component to floating point and clamps them to the range [0,1].

GL_RGBA_INTEGER

Each element contains all four components.

GL_DEPTH_COMPONENT

Each element is a single depth value. The GL converts it to floating point, and clamps to the range [0,1].

GL_DEPTH_STENCIL

Each element is a pair of depth and stencil values. The depth component of the pair is interpreted as in GL_DEPTH_COMPONENT. The stencil component is interpreted based on specified the depth + stencil internal format.

GL_LUMINANCE_ALPHA

Each element is an luminance/alpha double. The GL converts each component to floating point, clamps to the range [0,1], and assembles them into an RGBA element by placing the luminance value in the red, green and blue channels.

GL_LUMINANCE

Each element is a single luminance component. The GL converts it to floating point, clamps to the range [0,1], and assembles it into an RGBA element by placing the luminance value in the red, green and blue channels, and attaching 1.0 to the alpha channel.

GL_ALPHA

Each element is a single alpha component. The GL converts it to floating point, clamps to the range [0,1], and assembles it into an RGBA element by placing attaching 0.0 to the red, green and blue channels.

If an application wants to store the texture at a certain resolution or in a certain format, it can request the resolution and format with internalFormat. The GL will choose an internal representation with least the internal component sizes, and exactly the component types shown for that format, although it may not match exactly.

internalFormat may be one of the unsized (base) internal formats shown, together with valid format and type combinations, in Table 1, below

Table 1. Unsized Internal Formats
Unsized Internal Format Format Type RGBA and Luminance Values Internal Components
GL_RGB GL_RGB GL_UNSIGNED_BYTE, GL_UNSIGNED_SHORT_5_6_5 Red, Green, Blue R, G, B
GL_RGBA GL_RGBA GL_UNSIGNED_BYTE, GL_UNSIGNED_SHORT_4_4_4_4, GL_UNSIGNED_SHORT_5_5_5_1 Red, Green, Blue, Alpha R, G, B, A
GL_LUMINANCE_ALPHA GL_LUMINANCE_ALPHA GL_UNSIGNED_BYTE Luminance, Alpha L, A
GL_LUMINANCE GL_LUMINANCE GL_UNSIGNED_BYTE Luminance L
GL_ALPHA GL_ALPHA GL_UNSIGNED_BYTE Alpha A


internalFormat may also be one of the sized internal formats shown, together with valid format and type combinations, in Table 2, below

Table 2. Sized Internal Formats
Sized Internal Format Format Type Red Bits Green Bits Blue Bits Alpha Bits Shared Bits Color renderable Texture filterable
GL_R8 GL_RED GL_UNSIGNED_BYTE 8         Y Y
GL_R8_SNORM GL_RED GL_BYTE s8           Y
GL_R16F GL_RED GL_HALF_FLOAT,GL_FLOAT f16           Y
GL_R32F GL_RED GL_FLOAT f32            
GL_R8UI GL_RED_INTEGER GL_UNSIGNED_BYTE ui8         Y  
GL_R8I GL_RED_INTEGER GL_BYTE i8         Y  
GL_R16UI GL_RED_INTEGER GL_UNSIGNED_SHORT ui16         Y  
GL_R16I GL_RED_INTEGER GL_SHORT i16         Y  
GL_R32UI GL_RED_INTEGER GL_UNSIGNED_INT ui32         Y  
GL_R32I GL_RED_INTEGER GL_INT i32         Y  
GL_RG8 GL_RG GL_UNSIGNED_BYTE 8 8       Y Y
GL_RG8_SNORM GL_RG GL_BYTE s8 s8         Y
GL_RG16F GL_RG GL_HALF_FLOAT,GL_FLOAT f16 f16         Y
GL_RG32F GL_RG GL_FLOAT f32 f32          
GL_RG8UI GL_RG_INTEGER GL_UNSIGNED_BYTE ui8 ui8       Y  
GL_RG8I GL_RG_INTEGER GL_BYTE i8 i8       Y  
GL_RG16UI GL_RG_INTEGER GL_UNSIGNED_SHORT ui16 ui16       Y  
GL_RG16I GL_RG_INTEGER GL_SHORT i16 i16       Y  
GL_RG32UI GL_RG_INTEGER GL_UNSIGNED_INT ui32 ui32       Y  
GL_RG32I GL_RG_INTEGER GL_INT i32 i32       Y  
GL_RGB8 GL_RGB GL_UNSIGNED_BYTE 8 8 8     Y Y
GL_SRGB8 GL_RGB GL_UNSIGNED_BYTE 8 8 8       Y
GL_RGB565 GL_RGB GL_UNSIGNED_BYTE, GL_UNSIGNED_SHORT_5_6_5 5 6 5     Y Y
GL_RGB8_SNORM GL_RGB GL_BYTE s8 s8 s8       Y
GL_R11F_G11F_B10F GL_RGB GL_UNSIGNED_INT_10F_11F_11F_REV, GL_HALF_FLOAT, GL_FLOAT f11 f11 f10       Y
GL_RGB9_E5 GL_RGB GL_UNSIGNED_INT_5_9_9_9_REV, GL_HALF_FLOAT, GL_FLOAT 9 9 9   5   Y
GL_RGB16F GL_RGB GL_HALF_FLOAT, GL_FLOAT f16 f16 f16       Y
GL_RGB32F GL_RGB GL_FLOAT f32 f32 f32        
GL_RGB8UI GL_RGB_INTEGER GL_UNSIGNED_BYTE ui8 ui8 ui8        
GL_RGB8I GL_RGB_INTEGER GL_BYTE i8 i8 i8        
GL_RGB16UI GL_RGB_INTEGER GL_UNSIGNED_SHORT ui16 ui16 ui16        
GL_RGB16I GL_RGB_INTEGER GL_SHORT i16 i16 i16        
GL_RGB32UI GL_RGB_INTEGER GL_UNSIGNED_INT ui32 ui32 ui32        
GL_RGB32I GL_RGB_INTEGER GL_INT i32 i32 i32        
GL_RGBA8 GL_RGBA GL_UNSIGNED_BYTE 8 8 8 8   Y Y
GL_SRGB8_ALPHA8 GL_RGBA GL_UNSIGNED_BYTE 8 8 8 8   Y Y
GL_RGBA8_SNORM GL_RGBA GL_BYTE s8 s8 s8 s8     Y
GL_RGB5_A1 GL_RGBA GL_UNSIGNED_BYTE, GL_UNSIGNED_SHORT_5_5_5_1, GL_UNSIGNED_INT_2_10_10_10_REV 5 5 5 1   Y Y
GL_RGBA4 GL_RGBA GL_UNSIGNED_BYTE, GL_UNSIGNED_SHORT_4_4_4_4 4 4 4 4   Y Y
GL_RGB10_A2 GL_RGBA GL_UNSIGNED_INT_2_10_10_10_REV 10 10 10 2   Y Y
GL_RGBA16F GL_RGBA GL_HALF_FLOAT, GL_FLOAT f16 f16 f16 f16     Y
GL_RGBA32F GL_RGBA GL_FLOAT f32 f32 f32 f32      
GL_RGBA8UI GL_RGBA_INTEGER GL_UNSIGNED_BYTE ui8 ui8 ui8 ui8   Y  
GL_RGBA8I GL_RGBA_INTEGER GL_BYTE i8 i8 i8 i8   Y  
GL_RGB10_A2UI GL_RGBA_INTEGER GL_UNSIGNED_INT_2_10_10_10_REV ui10 ui10 ui10 ui2   Y  
GL_RGBA16UI GL_RGBA_INTEGER GL_UNSIGNED_SHORT ui16 ui16 ui16 ui16   Y  
GL_RGBA16I GL_RGBA_INTEGER GL_SHORT i16 i16 i16 i16   Y  
GL_RGBA32I GL_RGBA_INTEGER GL_INT i32 i32 i32 i32   Y  
GL_RGBA32UI GL_RGBA_INTEGER GL_UNSIGNED_INT ui32 ui32 ui32 ui32   Y  
Sized Internal Format Format Type Depth Bits Stencil Bits
GL_DEPTH_COMPONENT16 GL_DEPTH_COMPONENT GL_UNSIGNED_SHORT, GL_UNSIGNED_INT 16  
GL_DEPTH_COMPONENT24 GL_DEPTH_COMPONENT GL_UNSIGNED_INT 24  
GL_DEPTH_COMPONENT32F GL_DEPTH_COMPONENT GL_FLOAT f32  
GL_DEPTH24_STENCIL8 GL_DEPTH_STENCIL GL_UNSIGNED_INT_24_8 24 8
GL_DEPTH32F_STENCIL8 GL_DEPTH_STENCIL GL_FLOAT_32_UNSIGNED_INT_24_8_REV f32 8


If the internalFormat parameter is GL_SRGB8, or GL_SRGB8_ALPHA8, the texture is treated as if the red, green, or blue components are encoded in the sRGB color space. Any alpha component is left unchanged. The conversion from the sRGB encoded component c s to a linear component c l is:

c l = { c s 12.92 if c s 0.04045 ( c s + 0.055 1.055 ) 2.4 if c s > 0.04045

Assume c s is the sRGB component in the range [0,1].

A one-component texture image uses only the red component of the RGBA color extracted from data. A two-component image uses the R and G values. A three-component image uses the R, G, and B values. A four-component image uses all of the RGBA components.

Image-based shadowing can be enabled by comparing texture r coordinates to depth texture values to generate a boolean result. See glTexParameter for details on texture comparison.

Notes

The glPixelStorei mode affects texture images.

data may be a null pointer. In this case, texture memory is allocated to accommodate a texture of width width and height height. You can then download subtextures to initialize this texture memory. The image is undefined if the user tries to apply an uninitialized portion of the texture image to a primitive.

glTexImage2D specifies the two-dimensional texture for the texture object bound to the current texture unit, specified with glActiveTexture.

Errors

GL_INVALID_ENUM is generated if target is not GL_TEXTURE_2D, GL_TEXTURE_CUBE_MAP_POSITIVE_X, GL_TEXTURE_CUBE_MAP_NEGATIVE_X, GL_TEXTURE_CUBE_MAP_POSITIVE_Y, GL_TEXTURE_CUBE_MAP_NEGATIVE_Y, GL_TEXTURE_CUBE_MAP_POSITIVE_Z, or GL_TEXTURE_CUBE_MAP_NEGATIVE_Z.

GL_INVALID_ENUM is generated if target is one of the six cube map 2D image targets and the width and height parameters are not equal.

GL_INVALID_ENUM is generated if type is not a type constant.

GL_INVALID_VALUE is generated if width is less than 0 or greater than GL_MAX_TEXTURE_SIZE.

GL_INVALID_VALUE is generated if level is less than 0.

GL_INVALID_VALUE may be generated if level is greater than log 2 max , where max is the returned value of GL_MAX_TEXTURE_SIZE.

GL_INVALID_VALUE is generated if internalFormat is not one of the accepted resolution and format symbolic constants.

GL_INVALID_VALUE is generated if width or height is less than 0 or greater than GL_MAX_TEXTURE_SIZE.

GL_INVALID_VALUE is generated if border is not 0.

GL_INVALID_OPERATION is generated if the combination of internalFormat, format and type is not one of those in the tables above.

GL_INVALID_OPERATION is generated if storage for the texture has been previously specified with glTexStorage2D.

GL_INVALID_OPERATION is generated if a non-zero buffer object name is bound to the GL_PIXEL_UNPACK_BUFFER target and the buffer object's data store is currently mapped.

GL_INVALID_OPERATION is generated if a non-zero buffer object name is bound to the GL_PIXEL_UNPACK_BUFFER target and the data would be unpacked from the buffer object such that the memory reads required would exceed the data store size.

GL_INVALID_OPERATION is generated if a non-zero buffer object name is bound to the GL_PIXEL_UNPACK_BUFFER target and data is not evenly divisible into the number of bytes needed to store in memory a datum indicated by type.

Associated Gets

glGet with argument GL_PIXEL_UNPACK_BUFFER_BINDING

Examples

Create a framebuffer object with a texture-based color attachment and a texture-based depth attachment. Using texture-based attachments allows sampling of those textures in shaders.
// 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);
Create a texture object with linear mipmaps and edge clamping.
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() insteads.

glBindTexture(GL_TEXTURE_2D, 0);

API Version Support

OpenGL ES API Version
Function Name 2.0 3.0 3.1
glTexImage2D
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