/// <summary>
/// OnRenderFrame is called on every frame for rendering
/// </summary>
/// <param name="e">event arguments</param>
protected override void OnRenderFrame(FrameEventArgs e)
{
base.OnRenderFrame(e);
// Clear the color & depth buffer
gl.Clear(ClearBufferMask.ColorBufferBit |
ClearBufferMask.DepthBufferBit);
// Start with identity every frame
_viewMatrix.Identity();
// View transform: move the coordinate system away from the camera
_viewMatrix.Translate(0, 0, _camZ);
// View transform: rotate the coordinate system increasingly
_viewMatrix.Rotate(_rotX + _deltaX, 1, 0, 0);
_viewMatrix.Rotate(_rotY + _deltaY, 0, 1, 0);
// Transform light position & direction into view space
SLVec3f lightPosVS = _viewMatrix * _lightPos;
// The light dir is not a position. We only take the rotation of the mv matrix.
SLMat3f viewRot = _viewMatrix.Mat3();
SLVec3f lightDirVS = viewRot * _lightDir;
// Rotate the model so that we see it
_modelMatrix.Identity();
_modelMatrix.Rotate(90, -1, 0, 0);
// Build the combined modelview-projection matrix
SLMat4f mvp = new SLMat4f(_projectionMatrix);
SLMat4f mv = new SLMat4f(_viewMatrix);
mv.Multiply(_modelMatrix);
mvp.Multiply(mv);
// Build normal matrix
SLMat3f nm = mv.InverseTransposed();
// Pass the matrix uniform variables
unsafe
{ gl.UniformMatrix4(_mvMatrixLoc, 1, false, mv.m);
gl.UniformMatrix3(_nMatrixLoc, 1, false, nm.m);
gl.UniformMatrix4(_mvpMatrixLoc, 1, false, mvp.m);
// Pass lighting uniforms variables
gl.Uniform4(_globalAmbiLoc, 1, (float[])_globalAmbi);
gl.Uniform3(_lightPosVSLoc, 1, (float[])lightPosVS);
gl.Uniform3(_lightSpotDirVSLoc, 1, (float[])lightDirVS);
gl.Uniform4(_lightAmbientLoc, 1, (float[])_lightAmbient);
gl.Uniform4(_lightDiffuseLoc, 1, (float[])_lightDiffuse);
gl.Uniform4(_lightSpecularLoc, 1, (float[])_lightSpecular);
gl.Uniform4(_matAmbientLoc, 1, (float[])_matAmbient);
gl.Uniform4(_matDiffuseLoc, 1, (float[])_matDiffuse);
gl.Uniform4(_matSpecularLoc, 1, (float[])_matSpecular);
gl.Uniform4(_matEmissiveLoc, 1, (float[])_matEmissive); }
gl.Uniform1(_matShininessLoc, _matShininess);
gl.Uniform1(_texture0Loc, 0);
//////////////////////
// Draw with 2 VBOs //
//////////////////////
// Enable all of the vertex attribute arrays
gl.EnableVertexAttribArray(_pLoc);
gl.EnableVertexAttribArray(_nLoc);
gl.EnableVertexAttribArray(_tLoc);
// Activate VBOs
gl.BindBuffer(BufferTarget.ArrayBuffer, _vboV);
gl.BindBuffer(BufferTarget.ElementArrayBuffer, _vboI);
// Activate Texture
gl.BindTexture(TextureTarget.Texture2D, _textureID);
// For VBO only offset instead of data pointer
int stride = 32;
int offsetN = 3 * sizeof(float);
int offsetT = 6 * sizeof(float);
gl.VertexAttribPointer(_pLoc, 3, VertexAttribPointerType.Float, false, stride, 0);
gl.VertexAttribPointer(_nLoc, 3, VertexAttribPointerType.Float, false, stride, offsetN);
gl.VertexAttribPointer(_tLoc, 2, VertexAttribPointerType.Float, false, stride, offsetT);
/////////////////////////////////////////////////////////////////////////////
// Draw cube model triangles by indexes
gl.DrawElements(BeginMode.Triangles, _numI, DrawElementsType.UnsignedInt, 0);
/////////////////////////////////////////////////////////////////////////////
// Deactivate buffers
gl.BindBuffer(BufferTarget.ArrayBuffer, 0);
gl.BindBuffer(BufferTarget.ElementArrayBuffer, 0);
// Disable the vertex arrays
gl.DisableVertexAttribArray(_pLoc);
gl.DisableVertexAttribArray(_nLoc);
gl.DisableVertexAttribArray(_tLoc);
// Fast copy the back buffer to the front buffer. This is OS dependent.
SwapBuffers();
// Check for errors
glUtils.GetGLError("OnRenderFrame", true);
}