swr: [rasterizer core] implement legacy depth bias enable

Reviewed-by: Bruce Cherniak <bruce.cherniak@intel.com>

src/gallium/drivers/swr/rasterizer/core/api.cpp

@@ -767,7 +767,7 @@ void SetupPipeline(DRAW_CONTEXT *pDC)
     const SWR_RASTSTATE &rastState = pState->state.rastState;
     const SWR_PS_STATE &psState = pState->state.psState;
     BACKEND_FUNCS& backendFuncs = pState->backendFuncs;
-    const uint32_t forcedSampleCount = (rastState.bForcedSampleCount) ? 1 : 0;
+    const uint32_t forcedSampleCount = (rastState.forcedSampleCount) ? 1 : 0;
 
     // setup backend
     if (psState.pfnPixelShader == nullptr)
@@ -776,7 +776,7 @@ void SetupPipeline(DRAW_CONTEXT *pDC)
     }
     else
     {
-        const bool bMultisampleEnable = ((rastState.sampleCount > SWR_MULTISAMPLE_1X) || rastState.bForcedSampleCount) ? 1 : 0;
+        const bool bMultisampleEnable = ((rastState.sampleCount > SWR_MULTISAMPLE_1X) || rastState.forcedSampleCount) ? 1 : 0;
         const uint32_t centroid = ((psState.barycentricsMask & SWR_BARYCENTRIC_CENTROID_MASK) > 0) ? 1 : 0;
         const uint32_t canEarlyZ = (psState.forceEarlyZ || (!psState.writesODepth && !psState.usesSourceDepth && !psState.usesUAV)) ? 1 : 0;
 

src/gallium/drivers/swr/rasterizer/core/rasterizer.cpp

@@ -363,7 +363,13 @@ INLINE float ComputeDepthBias(const SWR_RASTSTATE* pState, const SWR_TRIANGLE_DE
         scale *= ComputeMaxDepthSlope(pTri);
     }
 
-    float bias = pState->depthBias * ComputeBiasFactor(pState, pTri, z) + scale;
+    float bias = pState->depthBias;
+    if (!pState->depthBiasPreAdjusted)
+    {
+        bias *= ComputeBiasFactor(pState, pTri, z);
+    }
+    bias += scale;
+
     if (pState->depthBiasClamp > 0.0f)
     {
         bias = std::min(bias, pState->depthBiasClamp);

src/gallium/drivers/swr/rasterizer/core/state.h

@@ -495,7 +495,6 @@ struct SWR_SURFACE_STATE
     uint32_t lod;               // for render targets, the lod being rendered to
     uint32_t arrayIndex;        // for render targets, the array index being rendered to for arrayed surfaces
     SWR_TILE_MODE tileMode;     // @llvm_enum
-    bool bInterleavedSamples;   // are MSAA samples stored interleaved or planar
     uint32_t halign;
     uint32_t valign;
     uint32_t xOffset;
@@ -504,6 +503,8 @@ struct SWR_SURFACE_STATE
     uint32_t lodOffsets[2][15]; // lod offsets for sampled surfaces
 
     uint8_t *pAuxBaseAddress;   // Used for compression, append/consume counter, etc.
+
+    bool bInterleavedSamples;   // are MSAA samples stored interleaved or planar
 };
 
 // vertex fetch state
@@ -895,22 +896,22 @@ enum SWR_MSAA_RASTMODE
 //////////////////////////////////////////////////////////////////////////
 struct SWR_RASTSTATE
 {
-    uint32_t cullMode : 2;
-    uint32_t fillMode : 2;
-    uint32_t frontWinding : 1;
-    uint32_t scissorEnable : 1;
-    uint32_t depthClipEnable : 1;
+    uint32_t cullMode               : 2;
+    uint32_t fillMode               : 2;
+    uint32_t frontWinding           : 1;
+    uint32_t scissorEnable          : 1;
+    uint32_t depthClipEnable        : 1;
+    uint32_t pointParam             : 1;
+    uint32_t pointSpriteEnable      : 1;
+    uint32_t pointSpriteTopOrigin   : 1;
+    uint32_t msaaRastEnable         : 1;
+    uint32_t forcedSampleCount      : 1;
+    uint32_t pixelOffset            : 1;
+    uint32_t depthBiasPreAdjusted   : 1;    ///< depth bias constant is in float units, not per-format Z units
+
     float pointSize;
     float lineWidth;
 
-    // point size output from the VS
-    bool pointParam;
-
-    // point sprite
-    bool pointSpriteEnable;
-    bool pointSpriteTopOrigin;
-
-    // depth bias
     float depthBias;
     float slopeScaledDepthBias;
     float depthBiasClamp;
@@ -918,14 +919,11 @@ struct SWR_RASTSTATE
 
     ///@todo: MSAA lines
     // multisample state for MSAA lines
-    bool msaaRastEnable;
     SWR_MSAA_RASTMODE rastMode;    // @llvm_enum
 
     // sample count the rasterizer is running at
     SWR_MULTISAMPLE_COUNT sampleCount;  // @llvm_enum
-    bool bForcedSampleCount;
     uint32_t pixelLocation;     // UL or Center
-    bool pixelOffset;           // offset pixel positions by .5 in both the horizontal and vertical direction
     SWR_MULTISAMPLE_POS iSamplePos[SWR_MAX_NUM_MULTISAMPLES];   
     SWR_MSAA_SAMPLE_PATTERN samplePattern;   // @llvm_enum
 

src/gallium/drivers/swr/swr_state.cpp

@@ -831,7 +831,7 @@ swr_update_derived(struct pipe_context *pipe,
       rastState->msaaRastEnable = false;
       rastState->rastMode = SWR_MSAA_RASTMODE_OFF_PIXEL;
       rastState->sampleCount = SWR_MULTISAMPLE_1X;
-      rastState->bForcedSampleCount = false;
+      rastState->forcedSampleCount = false;
 
       bool do_offset = false;
       switch (rasterizer->fill_front) {