グローの適用
グローの適用
この例では、2 つのテクニックを使用している。1 番目のテクニックは GlowOnly といい、オブジェクトにグローを適用する。GlowOnly は、Unskinned 関数を使ってライトを計算し、テクスチャ座標をコピーする。さらに Unskinned 関数は、ヘルパー関数 TransformUnskinned を使って、位置座標および法線データをトランスフォームする。
2 番目のテクニックは GlowAndNormal といい、2 つのパスから構成される。第 1 パスでオブジェクトを通常どおり描画し、第 2 パスでアウトラインを描画する。
この例は、上位レベル言語のサンプルを表し、次に示す例ではコンパイルは行わない。
例
// effect.fx
texture tex0 < string name = "tiger.bmp"; >;
texture tex1 < string name = "banana.bmp"; >;
string XFile = "tiger.x"; // Model to load
string BIMG = "lake.bmp"; // Background image
DWORD BCLR = 0xff202080; // Background color (if no image)
// Declare the required matrices with the appropriate semantics
// so that the viewer can supply the necessary matrix information.
float4x4 mProjection :PROJECTION;
float4x3 mWorldView :WORLDVIEW;
float4x4 mViewProjection :VIEWPROJECTION;
// Declare data used by the shaders that the application can modify.
float3 vLightDirection = {0.0, 0.0, -1.0 };
float vDisplace = 0.015;
float4 vGlowColor = { 0.5, 0.2, 0.2, 1.0 };
float4 vGlowAmbient = { 0.2, 0.2, 0.0, 0.0 };
// Set up an output structure defining the output to the pixel shader.
struct VS_OUTPUT_TEXCOORD0
{
float4 Position :POSITION;
float4 Diffuse :COLOR;
float2 Texture0 :TEXCOORD0;
};
// Helper function to transform position/normal into view space
void TransformUnskinned
(
float4 vPos,
float3 vNormal,
float3 vTransformedPosition,
float3 vTransformedNormal
)
{
// Transform the position into view space
vTransformedPosition = mul(vPos, mWorldView);
// Transform the normal into view space (just use the upper 3x3 of WorldView)
vTransformedNormal = mul(vNormal, (float3x3)mWorldView);
}
// Draws unskinned object with one texture and one directional light.
VS_OUTPUT_TEXCOORD0 Unskinned
(
float4 vPos :POSITION,
float3 vNormal :NORMAL,
float2 vTexCoord0 :TEXCOORD0
)
{
float3 vTransformedPosition = {0,0,0};
float3 vTransformedNormal = {0,0,0};
VS_OUTPUT_TEXCOORD0 Output;
float fDot;
// Transform the position/normal into view space.
TransformUnskinned(vPos, vNormal, vTransformedPosition, vTransformedNormal);
// Calculate amount of light from the one light direction.
fDot = dot(vTransformedNormal, vLightDirection);
// Transform view space position into screen space.
Output.Position = mul(float4(vTransformedPosition, 1.0), mProjection);
// Multiple amount of light times light color.
// Note:Color could be negative with this equation, but will be
// clamped to zero before pixel shader.
Output.Diffuse = float4(1.0f, 1.0f, 1.0f, 1.0f) * fDot;
// Just copy the texture coordinate through.
Output.Texture0 = vTexCoord0;
return Output;
}
// Declare the output of the GlowSkinned vertex shader to the pixel shader.
struct VS_OUTPUT
{
float4 Position :POSITION;
float4 Diffuse :COLOR;
};
// Draws a transparent hull of the unskinned object.
VS_OUTPUT GlowUnskinned
(
float4 vPos :POSITION,
float3 vNormal :NORMAL
)
{
float3 vTransformedPosition = {0,0,0};
float3 vTransformedNormal = {0,0,0};
VS_OUTPUT Output;
float fPower;
// For standard "glow" this is the view direction.
float3 vGlowAxis = float3(0, 0, 1);
// Transform the position and normal into world space.
TransformUnskinned(vPos, vNormal, vTransformedPosition, vTransformedNormal);
// Displace the position by the normal, so that the glow will not
// overlap the non-glowed version.
vTransformedPosition += vTransformedNormal * vDisplace;
// The glow is determined by the angle between the normal and the glow axis.
// This ends up being similar to a fresnel approximation.
fPower = dot(vTransformedNormal, vGlowAxis);
fPower = 1.0f - fPower * fPower;
fPower *= fPower;
// Transform position into screen space from view space.
Output.Position = mul(float4(vTransformedPosition, 1.0), mProjection);
// Output color is the compute power times the glow color.
Output.Diffuse = vGlowColor * fPower + vGlowAmbient;
return Output;
}
// first technique - unskinned
// first pass draw the object normally
// second pass draw the outline
technique GlowOnly
{
pass P1
{
// Generate a 1_1 vertex shader to draw the outline of the object.
VertexShader = compile vs_1_1 GlowUnskinned();
Texture[0] = NULL;
// Enable alpha blending
AlphaBlendEnable = True;
SrcBlend = One;
DestBlend = One;
// Set up TSS stages to just use the diffuse color.
ColorOp[0] = SelectArg2;
ColorArg2[0] = Diffuse;
AlphaOp[0] = SelectArg2;
AlphaArg2[0] = Diffuse;
ColorOp[1] = Disable;
AlphaOp[1] = Disable;
}
}
// First technique - unskinned
// First pass draw the object normally
// Second pass draw the outline
technique GlowAndNormal
{
pass P0
{
// Generate a 1_1 vertex shader for unskinned
// single texture/one directional light.
VertexShader = compile vs_1_1 Unskinned();
// Set up texture stage info for single texture.
ColorOp[0] = Modulate;
ColorArg1[0] = Texture;
ColorArg2[0] = Current;
AlphaOp[0] = Disable;
// Set texture filtering.
MinFilter[0] = Linear;
MagFilter[0] = Linear;
MipFilter[0] = Point;
// Set texture into stage 0.
Texture[0] = (tex0);
// Disable Stage1.
ColorOp[1] = Disable;
AlphaOp[1] = Disable;
}
pass P1
{
// Generate a 1_1 vertex shader to draw the outline of the object.
VertexShader = compile vs_1_1 GlowUnskinned();
Texture[0] = NULL;
// Enable alpha blending.
AlphaBlendEnable = True;
SrcBlend = One;
DestBlend = One;
// Set up TSS stages to just use the diffuse color.
ColorOp[0] = SelectArg2;
ColorArg2[0] = Diffuse;
AlphaOp[0] = SelectArg2;
AlphaArg2[0] = Diffuse;
ColorOp[1] = Disable;
AlphaOp[1] = Disable;
}
}