public class AMDVertexShaderTessellator
extends java.lang.Object
The vertex shader tessellator gives new flexibility to the shader author to shade at a tessellated vertex, rather than just at a provided vertex.
In unextended vertex shading, the built-in attributes such as gl_Vertex, gl_Normal, and gl_MultiTexcoord0, together with the user defined attributes, are system provided values which are initialized prior to vertex shader invocation.
With vertex shading tessellation, additional vertex shader special values are available:
ivec3 gl_VertexTriangleIndex; // indices of the three control
// points for the vertex
vec3 gl_BarycentricCoord; // barycentric coordinates
// of the vertex
i o
|\
| \
*--*
|\ |\
| \| \
*--*--*
|\ |\ |\
| \| \| \
j o--*--*--o k
Figure 1 A Tessellated Triangle
o = control point (and tessellated vertex)
* = tessellated vertex
ivec4 gl_VertexQuadIndex; // indices for the four control
// points for the vertex
vec2 gl_UVCoord; // UV coordinates of the vertex
i o--*--*--o k
|\ |\ |\ |
| \| \| \|
*--*--*--*
|\ |\ |\ |
| \| \| \|
*--*--*--*
|\ |\ |\ |
| \| \| \|
j o--*--*--o l
Figure 2 A Tessellated Quad
o = control point (and tessellated vertex)
* = tessellated vertex
When this extension is enabled, conventional built-in attributes and user defined attributes are uninitialized. The shader writer is responsible for explicitly fetching all other vertex data either from textures, uniform buffers, or vertex buffers.
The shader writer is further responsible for interpolating the vertex data at the given barycentric coordinates or uv coordinates of the vertex.
Requires OpenGL 2.0.
| Modifier and Type | Field and Description |
|---|---|
static int |
GL_CONTINUOUS_AMD
Accepted by TessellationModeAMD.
|
static int |
GL_DISCRETE_AMD
Accepted by TessellationModeAMD.
|
static int |
GL_INT_SAMPLER_BUFFER_AMD
Returned by the
type parameter of GetActiveUniform. |
static int |
GL_SAMPLER_BUFFER_AMD
Returned by the
type parameter of GetActiveUniform. |
static int |
GL_TESSELLATION_FACTOR_AMD
Accepted by GetFloatv.
|
static int |
GL_TESSELLATION_MODE_AMD
Accepted by GetIntegerv.
|
static int |
GL_UNSIGNED_INT_SAMPLER_BUFFER_AMD
Returned by the
type parameter of GetActiveUniform. |
| Modifier and Type | Method and Description |
|---|---|
static void |
glTessellationFactorAMD(float factor) |
static void |
glTessellationModeAMD(int mode) |
public static final int GL_SAMPLER_BUFFER_AMD
type parameter of GetActiveUniform.public static final int GL_INT_SAMPLER_BUFFER_AMD
type parameter of GetActiveUniform.public static final int GL_UNSIGNED_INT_SAMPLER_BUFFER_AMD
type parameter of GetActiveUniform.public static final int GL_DISCRETE_AMD
public static final int GL_CONTINUOUS_AMD
public static final int GL_TESSELLATION_MODE_AMD
public static final int GL_TESSELLATION_FACTOR_AMD
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