dpsoftrast: fix off-by-0.5 in GL_NEAREST

git-svn-id: svn://svn.icculus.org/twilight/trunk/darkplaces@11009 d7cf8633-e32d-0410-b094-e92efae38249
::stable-branch::merge=4c54e85289e3b095a73574c0335b3b869b3417ae

diff --git a/dpsoftrast.c b/dpsoftrast.c
index 98841a62ecfdf41bb2afeeb6191f3f48334a9f00..4bed6ae13c1d738b06ccd228a1dce71acabd8dbb 100644 (file)
--- a/dpsoftrast.c
+++ b/dpsoftrast.c
@@ -2388,6 +2388,11 @@ void DPSOFTRAST_Draw_Span_Texture2DVarying(DPSOFTRAST_State_Thread *thread, cons
        tciwrapmask[1] = texture->mipmap[mip][3]-1;
        endtc[0] = (data[0] + slope[0]*startx) * zf[startx] * tcscale[0] - 0.5f;
        endtc[1] = (data[1] + slope[1]*startx) * zf[startx] * tcscale[1] - 0.5f;
+       if (filter)
+       {
+               endtc[0] -= 0.5f;
+               endtc[1] -= 0.5f;
+       }
        for (x = startx;x < endx;)
        {
                unsigned int subtc[2];
@@ -2401,8 +2406,13 @@ void DPSOFTRAST_Draw_Span_Texture2DVarying(DPSOFTRAST_State_Thread *thread, cons
                }
                tc[0] = endtc[0];
                tc[1] = endtc[1];
-               endtc[0] = (data[0] + slope[0]*nextsub) * zf[nextsub] * tcscale[0] - 0.5f;
-               endtc[1] = (data[1] + slope[1]*nextsub) * zf[nextsub] * tcscale[1] - 0.5f;
+               endtc[0] = (data[0] + slope[0]*nextsub) * zf[nextsub] * tcscale[0];
+               endtc[1] = (data[1] + slope[1]*nextsub) * zf[nextsub] * tcscale[1];
+               if (filter)
+               {
+                       endtc[0] -= 0.5f;
+                       endtc[1] -= 0.5f;
+               }
                substep[0] = (endtc[0] - tc[0]) * subscale;
                substep[1] = (endtc[1] - tc[1]) * subscale;
                subtc[0] = tc[0] * (1<<12);
@@ -2549,7 +2559,9 @@ void DPSOFTRAST_Draw_Span_Texture2DVaryingBGRA8(DPSOFTRAST_State_Thread *thread,
        tcscale = _mm_cvtepi32_ps(tcsize);
        data = _mm_mul_ps(_mm_movelh_ps(data, data), tcscale);
        slope = _mm_mul_ps(_mm_movelh_ps(slope, slope), tcscale);
-       endtc = _mm_sub_ps(_mm_mul_ps(_mm_add_ps(data, _mm_mul_ps(slope, _mm_set1_ps(startx))), _mm_load1_ps(&zf[startx])), _mm_set1_ps(0.5f));
+       endtc = _mm_mul_ps(_mm_add_ps(data, _mm_mul_ps(slope, _mm_set1_ps(startx))), _mm_load1_ps(&zf[startx]));
+       if (filter)
+               endtc = _mm_sub_ps(endtc, _mm_set1_ps(0.5f));
        endsubtc = _mm_cvtps_epi32(_mm_mul_ps(endtc, _mm_set1_ps(65536.0f)));
        tcoffset = _mm_add_epi32(_mm_slli_epi32(_mm_shuffle_epi32(tcsize, _MM_SHUFFLE(0, 0, 0, 0)), 18), _mm_set1_epi32(4));
        tcmax = _mm_packs_epi32(tcmask, tcmask);
@@ -2564,7 +2576,9 @@ void DPSOFTRAST_Draw_Span_Texture2DVaryingBGRA8(DPSOFTRAST_State_Thread *thread,
                }       
                tc = endtc;
                subtc = endsubtc;
-               endtc = _mm_sub_ps(_mm_mul_ps(_mm_add_ps(data, _mm_mul_ps(slope, _mm_set1_ps(nextsub))), _mm_load1_ps(&zf[nextsub])), _mm_set1_ps(0.5f));
+               endtc = _mm_mul_ps(_mm_add_ps(data, _mm_mul_ps(slope, _mm_set1_ps(nextsub))), _mm_load1_ps(&zf[nextsub]));
+               if (filter)
+                       endtc = _mm_sub_ps(endtc, _mm_set1_ps(0.5f));
                substep = _mm_cvtps_epi32(_mm_mul_ps(_mm_sub_ps(endtc, tc), subscale));
                endsubtc = _mm_cvtps_epi32(_mm_mul_ps(endtc, _mm_set1_ps(65536.0f)));
                subtc = _mm_unpacklo_epi64(subtc, _mm_add_epi32(subtc, substep));
@@ -4475,7 +4489,7 @@ void DPSOFTRAST_PixelShader_Refraction(DPSOFTRAST_State_Thread *thread, const DP
                }
                else
                {
-                       int tci[2] = { ScreenTexCoord[0] * texture->mipmap[0][2] - 0.5f, ScreenTexCoord[1] * texture->mipmap[0][3] - 0.5f };
+                       int tci[2] = { ScreenTexCoord[0] * texture->mipmap[0][2], ScreenTexCoord[1] * texture->mipmap[0][3] };
                        tci[0] = tci[0] >= 0 ? (tci[0] <= texture->mipmap[0][2]-1 ? tci[0] : texture->mipmap[0][2]-1) : 0;
                        tci[1] = tci[1] >= 0 ? (tci[1] <= texture->mipmap[0][3]-1 ? tci[1] : texture->mipmap[0][3]-1) : 0;
                        pixel[0] = pixelbase + 4 * (tci[1]*texture->mipmap[0][2]+tci[0]);