3D Vertex and Pixel Shaders - Game Coding Complete - page 516

// Pixel Shader
// —————————————————————————————————————————————————————————————

float4 GameCode4_PSMain( PS_INPUT Input ) : SV_TARGET
{

float4 vOutputColor;

if (g_bHasTexture)
vOutputColor =
g_txDiffuse.Sample( g_samLinear, Input.vTexcoord ) * Input.vDiffuse;
else
vOutputColor = Input.vDiffuse;
return vOutputColor;

}
The pixel shader is much simpler than the vertex shader, since all it has to do is mix
a texture sample with the diffuse color sent in from the vertex shader.
Since this pixel can process a texture, there are globals that store a Texture2D struc-
ture and a SamplerState , which map to the ID3D11ShaderResourceView and
ID3D11SamplerState resources you learned about in the texturing section earlier.
The VS_INPUT structure defines the data that is output from the vertex shader,
which will be the diffuse color calculated by the vertex shader and the texture coor-
dinate at the pixel location. The call to Sample grabs the texel from the texture,
based on the value of Input.vTexcoord . This value is multiplied by
Input.vDiffuse to blend the light, object color, and texture together. If no texture
is defined, vOutputColor is simply set to the Input.vDiffuse value.

C++ Helper Class for the Pixel Shader
Just as you saw with the vertex shader, there is a C++ class designed to set up the
pixel shader and communicate data to it.

class GameCode4_Hlsl_PixelShader
{
public:
GameCode4_Hlsl_PixelShader(std::string textureResource);
~GameCode4_Hlsl_PixelShader();

HRESULT OnRestore(Scene *pScene);
HRESULT SetupRender(Scene *pScene, const SceneNode *pNode);
HRESULT SetTexture(std::string textureName);
HRESULT SetTexture(ID3D11ShaderResourceView* const *pDiffuseRV,
ID3D11SamplerState * const *ppSamplers);
void EnableLights(bool enableLights) { m_enableLights = enableLights; }