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      1 /*
      2  * Copyright 2015 Google Inc.
      3  *
      4  * Use of this source code is governed by a BSD-style license that can be
      5  * found in the LICENSE file.
      6  */
      7 
      8 #include "Test.h"
      9 #if SK_SUPPORT_GPU
     10 #include "GrCaps.h"
     11 #include "GrContext.h"
     12 #include "SkCanvas.h"
     13 #include "SkSurface.h"
     14 
     15 // using anonymous namespace because these functions are used as template params.
     16 namespace {
     17 /** convert 0..1 srgb value to 0..1 linear */
     18 float srgb_to_linear(float srgb) {
     19     if (srgb <= 0.04045f) {
     20         return srgb / 12.92f;
     21     } else {
     22         return powf((srgb + 0.055f) / 1.055f, 2.4f);
     23     }
     24 }
     25 
     26 /** convert 0..1 linear value to 0..1 srgb */
     27 float linear_to_srgb(float linear) {
     28     if (linear <= 0.0031308) {
     29         return linear * 12.92f;
     30     } else {
     31         return 1.055f * powf(linear, 1.f / 2.4f) - 0.055f;
     32     }
     33 }
     34 }
     35 
     36 /** tests a conversion with an error tolerance */
     37 template <float (*CONVERT)(float)> static bool check_conversion(uint32_t input, uint32_t output,
     38                                                                 float error) {
     39     // alpha should always be exactly preserved.
     40     if ((input & 0xff000000) != (output & 0xff000000)) {
     41         return false;
     42     }
     43 
     44     for (int c = 0; c < 3; ++c) {
     45         uint8_t inputComponent = (uint8_t) ((input & (0xff << (c*8))) >> (c*8));
     46         float lower = SkTMax(0.f, (float) inputComponent - error);
     47         float upper = SkTMin(255.f, (float) inputComponent + error);
     48         lower = CONVERT(lower / 255.f);
     49         upper = CONVERT(upper / 255.f);
     50         SkASSERT(lower >= 0.f && lower <= 255.f);
     51         SkASSERT(upper >= 0.f && upper <= 255.f);
     52         uint8_t outputComponent = (output & (0xff << (c*8))) >> (c*8);
     53         if (outputComponent < SkScalarFloorToInt(lower * 255.f) ||
     54             outputComponent > SkScalarCeilToInt(upper * 255.f)) {
     55             return false;
     56         }
     57     }
     58     return true;
     59 }
     60 
     61 /** tests a forward and backward conversion with an error tolerance */
     62 template <float (*FORWARD)(float), float (*BACKWARD)(float)>
     63 static bool check_double_conversion(uint32_t input, uint32_t output, float error) {
     64     // alpha should always be exactly preserved.
     65     if ((input & 0xff000000) != (output & 0xff000000)) {
     66         return false;
     67     }
     68 
     69     for (int c = 0; c < 3; ++c) {
     70         uint8_t inputComponent = (uint8_t) ((input & (0xff << (c*8))) >> (c*8));
     71         float lower = SkTMax(0.f, (float) inputComponent - error);
     72         float upper = SkTMin(255.f, (float) inputComponent + error);
     73         lower = FORWARD(lower / 255.f);
     74         upper = FORWARD(upper / 255.f);
     75         SkASSERT(lower >= 0.f && lower <= 255.f);
     76         SkASSERT(upper >= 0.f && upper <= 255.f);
     77         uint8_t upperComponent = SkScalarCeilToInt(upper * 255.f);
     78         uint8_t lowerComponent = SkScalarFloorToInt(lower * 255.f);
     79         lower = SkTMax(0.f, (float) lowerComponent - error);
     80         upper = SkTMin(255.f, (float) upperComponent + error);
     81         lower = BACKWARD(lowerComponent / 255.f);
     82         upper = BACKWARD(upperComponent / 255.f);
     83         SkASSERT(lower >= 0.f && lower <= 255.f);
     84         SkASSERT(upper >= 0.f && upper <= 255.f);
     85         upperComponent = SkScalarCeilToInt(upper * 255.f);
     86         lowerComponent = SkScalarFloorToInt(lower * 255.f);
     87 
     88         uint8_t outputComponent = (output & (0xff << (c*8))) >> (c*8);
     89         if (outputComponent < lowerComponent || outputComponent > upperComponent) {
     90             return false;
     91         }
     92     }
     93     return true;
     94 }
     95 
     96 static bool check_srgb_to_linear_conversion(uint32_t srgb, uint32_t linear, float error) {
     97     return check_conversion<srgb_to_linear>(srgb, linear, error);
     98 }
     99 
    100 static bool check_linear_to_srgb_conversion(uint32_t linear, uint32_t srgb, float error) {
    101     return check_conversion<linear_to_srgb>(linear, srgb, error);
    102 }
    103 
    104 static bool check_linear_to_srgb_to_linear_conversion(uint32_t input, uint32_t output, float error) {
    105     return check_double_conversion<linear_to_srgb, srgb_to_linear>(input, output, error);
    106 }
    107 
    108 static bool check_srgb_to_linear_to_srgb_conversion(uint32_t input, uint32_t output, float error) {
    109     return check_double_conversion<srgb_to_linear, linear_to_srgb>(input, output, error);
    110 }
    111 
    112 typedef bool (*CheckFn) (uint32_t orig, uint32_t actual, float error);
    113 
    114 void read_and_check_pixels(skiatest::Reporter* reporter, GrTexture* texture, uint32_t* origData,
    115                            GrPixelConfig readConfig, CheckFn checker, float error,
    116                            const char* subtestName) {
    117     int w = texture->width();
    118     int h = texture->height();
    119     SkAutoTMalloc<uint32_t> readData(w * h);
    120     memset(readData.get(), 0, sizeof(uint32_t) * w * h);
    121     if (!texture->readPixels(0, 0, w, h, readConfig, readData.get())) {
    122         ERRORF(reporter, "Could not read pixels for %s.", subtestName);
    123         return;
    124     }
    125     for (int j = 0; j < h; ++j) {
    126         for (int i = 0; i < w; ++i) {
    127             uint32_t orig = origData[j * w + i];
    128             uint32_t read = readData[j * w + i];
    129 
    130             if (!checker(orig, read, error)) {
    131                 ERRORF(reporter, "Expected 0x%08x, read back as 0x%08x in %s at %d, %d).",
    132                        orig, read, subtestName, i, j);
    133                 return;
    134             }
    135         }
    136     }
    137 }
    138 
    139 // TODO: Add tests for copySurface between srgb/linear textures. Add tests for unpremul/premul
    140 // conversion during read/write along with srgb/linear conversions.
    141 DEF_GPUTEST_FOR_RENDERING_CONTEXTS(SRGBReadWritePixels, reporter, context) {
    142 #if defined(GOOGLE3)
    143     // Stack frame size is limited in GOOGLE3.
    144     static const int kW = 63;
    145     static const int kH = 63;
    146 #else
    147     static const int kW = 255;
    148     static const int kH = 255;
    149 #endif
    150     uint32_t origData[kW * kH];
    151     for (int j = 0; j < kH; ++j) {
    152         for (int i = 0; i < kW; ++i) {
    153             origData[j * kW + i] = (j << 24) | (i << 16) | (i << 8) | i;
    154         }
    155     }
    156 
    157     GrSurfaceDesc desc;
    158     desc.fFlags = kRenderTarget_GrSurfaceFlag;
    159     desc.fWidth = kW;
    160     desc.fHeight = kH;
    161     desc.fConfig = kSRGBA_8888_GrPixelConfig;
    162     if (context->caps()->isConfigRenderable(desc.fConfig, false) &&
    163         context->caps()->isConfigTexturable(desc.fConfig)) {
    164         SkAutoTUnref<GrTexture> tex(context->textureProvider()->createTexture(
    165                 desc, SkBudgeted::kNo));
    166         if (!tex) {
    167             ERRORF(reporter, "Could not create SRGBA texture.");
    168             return;
    169         }
    170 
    171         float error = context->caps()->shaderCaps()->floatPrecisionVaries() ? 1.2f  : 0.5f;
    172 
    173         // Write srgba data and read as srgba and then as rgba
    174         if (tex->writePixels(0, 0, kW, kH, kSRGBA_8888_GrPixelConfig, origData)) {
    175             // For the all-srgba case, we allow a small error only for devices that have
    176             // precision variation because the srgba data gets converted to linear and back in
    177             // the shader.
    178             float smallError = context->caps()->shaderCaps()->floatPrecisionVaries() ? 1.f :
    179                     0.0f;
    180             read_and_check_pixels(reporter, tex, origData, kSRGBA_8888_GrPixelConfig,
    181                                   check_srgb_to_linear_to_srgb_conversion, smallError,
    182                                   "write/read srgba to srgba texture");
    183             read_and_check_pixels(reporter, tex, origData, kRGBA_8888_GrPixelConfig,
    184                                   check_srgb_to_linear_conversion, error,
    185                                   "write srgba/read rgba with srgba texture");
    186         } else {
    187             ERRORF(reporter, "Could not write srgba data to srgba texture.");
    188         }
    189 
    190         // Now verify that we can write linear data
    191         if (tex->writePixels(0, 0, kW, kH, kRGBA_8888_GrPixelConfig, origData)) {
    192             // We allow more error on GPUs with lower precision shader variables.
    193             read_and_check_pixels(reporter, tex, origData, kSRGBA_8888_GrPixelConfig,
    194                                   check_linear_to_srgb_conversion, error,
    195                                   "write rgba/read srgba with srgba texture");
    196             read_and_check_pixels(reporter, tex, origData, kRGBA_8888_GrPixelConfig,
    197                                   check_linear_to_srgb_to_linear_conversion, error,
    198                                   "write/read rgba with srgba texture");
    199         } else {
    200             ERRORF(reporter, "Could not write rgba data to srgba texture.");
    201         }
    202 
    203         desc.fConfig = kRGBA_8888_GrPixelConfig;
    204         tex.reset(context->textureProvider()->createTexture(desc, SkBudgeted::kNo));
    205         if (!tex) {
    206             ERRORF(reporter, "Could not create RGBA texture.");
    207             return;
    208         }
    209 
    210         // Write srgba data to a rgba texture and read back as srgba and rgba
    211         if (tex->writePixels(0, 0, kW, kH, kSRGBA_8888_GrPixelConfig, origData)) {
    212             read_and_check_pixels(reporter, tex, origData, kSRGBA_8888_GrPixelConfig,
    213                                   check_srgb_to_linear_to_srgb_conversion, error,
    214                                   "write/read srgba to rgba texture");
    215             read_and_check_pixels(reporter, tex, origData, kRGBA_8888_GrPixelConfig,
    216                                   check_srgb_to_linear_conversion, error,
    217                                   "write srgba/read rgba to rgba texture");
    218         } else {
    219             ERRORF(reporter, "Could not write srgba data to rgba texture.");
    220         }
    221 
    222         // Write rgba data to a rgba texture and read back as srgba
    223         if (tex->writePixels(0, 0, kW, kH, kRGBA_8888_GrPixelConfig, origData)) {
    224             read_and_check_pixels(reporter, tex, origData, kSRGBA_8888_GrPixelConfig,
    225                                   check_linear_to_srgb_conversion, 1.2f,
    226                                   "write rgba/read srgba to rgba texture");
    227         } else {
    228             ERRORF(reporter, "Could not write rgba data to rgba texture.");
    229         }
    230     }
    231 }
    232 #endif
    233