[英]Ogre3d / Deferred rendering / Point light
我試圖使用ogre compositor框架設置延遲渲染器。 我嘗試在下面的代碼中實現一個點光着色器(作為全屏四邊形效果,沒有衰減或鏡面反射計算):
將延遲數據輸出到GBuffer的材料:
void ToGBufferVP
(
float4 iPosition : POSITION,
float3 iNormal : NORMAL,
float2 iUV0 : TEXCOORD,
out float4 oPosition : POSITION,
out float3 oViewPos : TEXCOORD0,
out float3 oNormal : TEXCOORD1,
out float2 oUV0 : TEXCOORD2,
uniform float4x4 cWorldViewProj,
uniform float4x4 cWorldView
)
{
oPosition = mul(cWorldViewProj, iPosition);
oNormal = mul(cWorldView, float4(iNormal,0)).xyz;
oViewPos = mul(cWorldView, iPosition).xyz;
oUV0 = iUV0;
}
void ToGBufferFP
(
float3 iViewPos : TEXCOORD0,
float3 iNormal : TEXCOORD1,
float2 iUV0 : TEXCOORD2,
out float4 oColor0 : COLOR0,
out float4 oColor1 : COLOR1,
uniform sampler2D sTex : register(s0),
uniform sampler2D sSpec : register(s1),
uniform float cFarDistance
)
{
oColor0.rgb = tex2D(sTex, iUV0);
oColor0.a = tex2D(sSpec, iUV0);
oColor1.rgb = normalize(iNormal);
oColor1.a = length(iViewPos) / cFarDistance;
}
頂點程序說明:
vertex_program ScreenQuadDebugLight_VS cg
{
source MyDeferredPostShader.hlsl
profiles vs_1_1 arbvp1
entry_point ScreenQuadDebugLight_VS
default_params
{
param_named_auto worldViewProj worldviewproj_matrix
}
}
片段程序說明:
fragment_program ScreenQuadDebugLight_PS cg
{
source MyDeferredPostShader.hlsl
profiles ps_2_0 arbfp1
entry_point ScreenQuadDebugLight_PS
default_params
{
param_named_auto vpWidth viewport_width
param_named_auto vpHeight viewport_height
param_named_auto flip render_target_flipping
param_named_auto farClipDistance far_clip_distance
param_named_auto lightPos light_position_view_space 0
}
}
輕材料腳本:
material DeferredShadingPostQuadLight
{
technique
{
pass
{
cull_hardware none
cull_software none
depth_func always_pass
vertex_program_ref ScreenQuadDebugLight_VS
{
}
fragment_program_ref ScreenQuadDebugLight_PS
{
}
texture_unit
{
tex_coord_set 0
tex_address_mode clamp
filtering none
}
texture_unit
{
tex_coord_set 1
tex_address_mode clamp
filtering none
}
}
}
}
淺色着色器:
void ScreenQuadDebugLight_VS
(
float4 Pos: POSITION,
out float4 oPos: POSITION,
out float4 oTexCoord : TEXCOORD0,
uniform float4x4 worldViewProj
)
{
float4 projPos = mul(worldViewProj, Pos);
oTexCoord = projPos;
oPos = projPos;
}
float4 ScreenQuadDebugLight_PS
(
float4 projPos : TEXCOORD0,
uniform sampler Tex0: register(s0),
uniform sampler Tex1: register(s1),
uniform float vpWidth,
uniform float vpHeight,
uniform float flip,
uniform float farClipDistance,
uniform float3 lightPos
) : COLOR
{
// Get homogenous coordinates
projPos.xy /= projPos.w;
// Compensate texture coordinate half pixel jitter
float2 texCoord = 0.5f * (float2(projPos.x, -projPos.y) + 1);
float2 halfPixel = float2(0.5/vpWidth, 0.5/vpHeight);
texCoord += halfPixel;
float3 ray = float3(projPos.x, projPos.y * flip, 1);
float4 a0 = tex2D(Tex0, texCoord); // Albedo and Specularity
float4 a1 = tex2D(Tex1, texCoord); // Normal and Depth
// Attributes
float3 colour = a0.rgb;
float specularity = a0.a;
float distance = a1.w;
float3 normal = a1.xyz;
float3 viewPos = normalize(ray);
viewPos.z = distance;
float3 objToLightVec = lightPos - viewPos;
float len_sq = dot(objToLightVec, objToLightVec);
float len = sqrt(len_sq);
float3 objToLightDir = normalize(objToLightVec);
float3 total_light_contrib;
total_light_contrib = max(0.0, dot(objToLightDir, normal));
return float4(total_light_contrib, 0.0);
}
這就是我在.cpp文件中聲明光的方式:
lLightSceneNodeHolder = mSceneMgr->getRootSceneNode()->createChildSceneNode();
Ogre::Light *light;
light = mSceneMgr->createLight();
light->setType(Ogre::Light::LT_POINT);
light->setPosition(Ogre::Vector3(0, 0, -0.7f));
light->setVisible(true);
light->setDiffuseColour(Ogre::ColourValue::White);
light->setSpecularColour(Ogre::ColourValue::White);
lLightSceneNodeHolder->attachObject(light);
我得到輸出,一切正常 - 除了我不能讓燈光正常工作。 G Buffer包含有效數據 - 視圖空間法線,線性z深度,紋理。 我也將視圖空間中的光位置作為參數 - 但是在矢量計算期間存在一些問題 - 並且輸出與點光源不同。 我在這做錯了什么?
謝謝!
PS我也嘗試通過合成器監聽器手動傳遞lightPos參數,但隨后燈光看起來更像是定向燈......
問題在於:
float3 ray = float3(projPos.x, projPos.y * flip, 1);
它必須乘以farCorner
值,這是相機視錐的遠角:
float3 ray = float3(projPos.x, projPos.y * flip, 1) * farCorner;
你可以通過使用獲得它
mCamera->getWorldSpaceCorners()[1];
然后將它插入到compositor偵聽器中,如下所示:
void LightListener::notifyMaterialSetup(Ogre::uint32 pass_id, Ogre::MaterialPtr &mat)
{
vpParams = mat->getBestTechnique()->getPass(0)->getVertexProgramParameters();
fpParams = mat->getBestTechnique()->getPass(0)->getFragmentProgramParameters();
}
void LightListener::notifyMaterialRender(Ogre::uint32 pass_id, Ogre::MaterialPtr &mat)
{
vpParams->setNamedConstant("lightPos", lightPos);
fpParams->setNamedConstant("farCorner", mCamera->getWorldSpaceCorners()[1]);
}
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