glDrawElementsInstancedBaseInstance

glDrawElementsInstancedBaseInstance: man4/glDrawElementsInstancedBaseInstance.xml

glDrawElementsInstancedBaseInstance behaves identically to glDrawElements except that primcount instances of the set of elements are executed and the value of the internal counter instanceID advances for each iteration. instanceID is an internal 32-bit integer counter that may be read by a vertex shader as gl_InstanceID. glDrawElementsInstancedBaseInstance has the same effect as:

if (mode, count, or type is invalid )
    generate appropriate error
else {
    for (int i = 0; i &lt; primcount ; i++) {
        instanceID = i;
        glDrawElements(mode, count, type, indices);
    }
    instanceID = 0;
}

Specific vertex attributes may be classified as through the use of glVertexAttribDivisor. Instanced vertex attributes supply per-instance vertex data to the vertex shader. The index of the vertex fetched from the enabled instanced vertex attribute arrays is calculated as gl _ InstanceID divisor + baseInstance. Note that baseinstance does not affect the shader-visible value of gl_InstanceID.

glDrawElementsInstancedBaseInstance is available only if the GL version is 4.2 or greater. GL_LINE_STRIP_ADJACENCY, GL_LINES_ADJACENCY, GL_TRIANGLE_STRIP_ADJACENCY and GL_TRIANGLES_ADJACENCY are available only if the GL version is 3.2 or greater.

@OpenGL_Version(OGLIntroducedIn.V4P2)

@OpenGL_Extension("GL_ARB_base_instance")

fn_glDrawElementsInstancedBaseInstance glDrawElementsInstancedBaseInstance;

glDrawElementsInstancedBaseInstance

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