/*
 * Copyright 2011 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */


#include "GrGLUtil.h"
#include "SkMatrix.h"
#if defined(SK_BUILD_FOR_STARBOARD)
#include "starboard/string.h"
#define sscanf SbStringScanF
#else
#include <stdio.h>
#endif

void GrGLClearErr(const GrGLInterface* gl) {
    while (GR_GL_NO_ERROR != gl->fFunctions.fGetError()) {}
}

namespace {
const char *get_error_string(uint32_t err) {
    switch (err) {
    case GR_GL_NO_ERROR:
        return "";
    case GR_GL_INVALID_ENUM:
        return "Invalid Enum";
    case GR_GL_INVALID_VALUE:
        return "Invalid Value";
    case GR_GL_INVALID_OPERATION:
        return "Invalid Operation";
    case GR_GL_OUT_OF_MEMORY:
        return "Out of Memory";
    case GR_GL_CONTEXT_LOST:
        return "Context Lost";
    }
    return "Unknown";
}
}

void GrGLCheckErr(const GrGLInterface* gl,
                  const char* location,
                  const char* call) {
    uint32_t err = GR_GL_GET_ERROR(gl);
    if (GR_GL_NO_ERROR != err) {
        GrPrintf("---- glGetError 0x%x(%s)", err, get_error_string(err));
        if (location) {
            GrPrintf(" at\n\t%s", location);
        }
        if (call) {
            GrPrintf("\n\t\t%s", call);
        }
        GrPrintf("\n");
    }
}

///////////////////////////////////////////////////////////////////////////////

#if GR_GL_LOG_CALLS
    bool gLogCallsGL = !!(GR_GL_LOG_CALLS_START);
#endif

#if GR_GL_CHECK_ERROR
    bool gCheckErrorGL = !!(GR_GL_CHECK_ERROR_START);
#endif

///////////////////////////////////////////////////////////////////////////////

GrGLStandard GrGLGetStandardInUseFromString(const char* versionString) {
    if (NULL == versionString) {
        SkDebugf("NULL GL version string.");
        return kNone_GrGLStandard;
    }

    int major, minor;

    // check for desktop
    int n = sscanf(versionString, "%d.%d", &major, &minor);
    if (2 == n) {
        return kGL_GrGLStandard;
    }

    // check for ES 1
    char profile[2];
    n = sscanf(versionString, "OpenGL ES-%c%c %d.%d", profile, profile+1, &major, &minor);
    if (4 == n) {
        // we no longer support ES1.
        return kNone_GrGLStandard;
    }

    // check for ES2
    n = sscanf(versionString, "OpenGL ES %d.%d", &major, &minor);
    if (2 == n) {
        return kGLES_GrGLStandard;
    }
    return kNone_GrGLStandard;
}

bool GrGLIsMesaFromVersionString(const char* versionString) {
    int major, minor, mesaMajor, mesaMinor;
    int n = sscanf(versionString, "%d.%d Mesa %d.%d", &major, &minor, &mesaMajor, &mesaMinor);
    if (4 == n) {
        return true;
    }

    // Mesa can also be used for OpenGL ES, so check for that as well.
    n = sscanf(versionString, "OpenGL ES %d.%d Mesa %d.%d", &major, &minor, &mesaMajor, &mesaMinor);
    return 4 == n;
}

bool GrGLIsChromiumFromRendererString(const char* rendererString) {
    return 0 == strcmp(rendererString, "Chromium");
}

GrGLVersion GrGLGetVersionFromString(const char* versionString) {
    if (NULL == versionString) {
        SkDebugf("NULL GL version string.");
        return GR_GL_INVALID_VER;
    }

    int major, minor;

    // check for mesa
    int mesaMajor, mesaMinor;
    int n = sscanf(versionString, "%d.%d Mesa %d.%d", &major, &minor, &mesaMajor, &mesaMinor);
    if (4 == n) {
        return GR_GL_VER(major, minor);
    }

    n = sscanf(versionString, "%d.%d", &major, &minor);
    if (2 == n) {
        return GR_GL_VER(major, minor);
    }

    char profile[2];
    n = sscanf(versionString, "OpenGL ES-%c%c %d.%d", profile, profile+1,
               &major, &minor);
    if (4 == n) {
        return GR_GL_VER(major, minor);
    }

    n = sscanf(versionString, "OpenGL ES %d.%d", &major, &minor);
    if (2 == n) {
        return GR_GL_VER(major, minor);
    }

    return GR_GL_INVALID_VER;
}

GrGLSLVersion GrGLGetGLSLVersionFromString(const char* versionString) {
    if (NULL == versionString) {
        SkDebugf("NULL GLSL version string.");
        return GR_GLSL_INVALID_VER;
    }

    int major, minor;

    int n = sscanf(versionString, "%d.%d", &major, &minor);
    if (2 == n) {
        return GR_GLSL_VER(major, minor);
    }

    n = sscanf(versionString, "OpenGL ES GLSL ES %d.%d", &major, &minor);
    if (2 == n) {
        return GR_GLSL_VER(major, minor);
    }

#ifdef SK_BUILD_FOR_ANDROID
    // android hack until the gpu vender updates their drivers
    n = sscanf(versionString, "OpenGL ES GLSL %d.%d", &major, &minor);
    if (2 == n) {
        return GR_GLSL_VER(major, minor);
    }
#endif

    return GR_GLSL_INVALID_VER;
}

GrGLVendor GrGLGetVendorFromString(const char* vendorString) {
    if (vendorString) {
        if (0 == strcmp(vendorString, "ARM")) {
            return kARM_GrGLVendor;
        }
        if (0 == strcmp(vendorString, "Imagination Technologies")) {
            return kImagination_GrGLVendor;
        }
        if (0 == strncmp(vendorString, "Intel ", 6) || 0 == strcmp(vendorString, "Intel")) {
            return kIntel_GrGLVendor;
        }
        if (0 == strcmp(vendorString, "Qualcomm")) {
            return kQualcomm_GrGLVendor;
        }
        if (0 == strcmp(vendorString, "NVIDIA Corporation")) {
                return kNVIDIA_GrGLVendor;
        }
    }
    return kOther_GrGLVendor;
}

GrGLRenderer GrGLGetRendererFromString(const char* rendererString) {
    if (rendererString) {
        if (0 == strcmp(rendererString, "NVIDIA Tegra 3")) {
            return kTegra3_GrGLRenderer;
        } else if (0 == strcmp(rendererString, "NVIDIA Tegra")) {
            return kTegra2_GrGLRenderer;
        }
    }
    return kOther_GrGLRenderer;
}

GrGLVersion GrGLGetVersion(const GrGLInterface* gl) {
    const GrGLubyte* v;
    GR_GL_CALL_RET(gl, v, GetString(GR_GL_VERSION));
    return GrGLGetVersionFromString((const char*) v);
}

GrGLSLVersion GrGLGetGLSLVersion(const GrGLInterface* gl) {
    const GrGLubyte* v;
    GR_GL_CALL_RET(gl, v, GetString(GR_GL_SHADING_LANGUAGE_VERSION));
    return GrGLGetGLSLVersionFromString((const char*) v);
}

GrGLVendor GrGLGetVendor(const GrGLInterface* gl) {
    const GrGLubyte* v;
    GR_GL_CALL_RET(gl, v, GetString(GR_GL_VENDOR));
    return GrGLGetVendorFromString((const char*) v);
}

GrGLRenderer GrGLGetRenderer(const GrGLInterface* gl) {
    const GrGLubyte* v;
    GR_GL_CALL_RET(gl, v, GetString(GR_GL_RENDERER));
    return GrGLGetRendererFromString((const char*) v);
}

template<> void GrGLGetMatrix<3>(GrGLfloat* dest, const SkMatrix& src) {
    // Col 0
    dest[0] = SkScalarToFloat(src[SkMatrix::kMScaleX]);
    dest[1] = SkScalarToFloat(src[SkMatrix::kMSkewY]);
    dest[2] = SkScalarToFloat(src[SkMatrix::kMPersp0]);

    // Col 1
    dest[3] = SkScalarToFloat(src[SkMatrix::kMSkewX]);
    dest[4] = SkScalarToFloat(src[SkMatrix::kMScaleY]);
    dest[5] = SkScalarToFloat(src[SkMatrix::kMPersp1]);

    // Col 2
    dest[6] = SkScalarToFloat(src[SkMatrix::kMTransX]);
    dest[7] = SkScalarToFloat(src[SkMatrix::kMTransY]);
    dest[8] = SkScalarToFloat(src[SkMatrix::kMPersp2]);
}

template<> void GrGLGetMatrix<4>(GrGLfloat* dest, const SkMatrix& src) {
    // Col 0
    dest[0]  = SkScalarToFloat(src[SkMatrix::kMScaleX]);
    dest[1]  = SkScalarToFloat(src[SkMatrix::kMSkewY]);
    dest[2]  = 0;
    dest[3]  = SkScalarToFloat(src[SkMatrix::kMPersp0]);

    // Col 1
    dest[4]  = SkScalarToFloat(src[SkMatrix::kMSkewX]);
    dest[5]  = SkScalarToFloat(src[SkMatrix::kMScaleY]);
    dest[6]  = 0;
    dest[7]  = SkScalarToFloat(src[SkMatrix::kMPersp1]);

    // Col 2
    dest[8]  = 0;
    dest[9]  = 0;
    dest[10] = 1;
    dest[11] = 0;

    // Col 3
    dest[12] = SkScalarToFloat(src[SkMatrix::kMTransX]);
    dest[13] = SkScalarToFloat(src[SkMatrix::kMTransY]);
    dest[14] = 0;
    dest[15] = SkScalarToFloat(src[SkMatrix::kMPersp2]);
}

GrGLenum GrToGLStencilFunc(GrStencilFunc basicFunc) {
    static const GrGLenum gTable[] = {
        GR_GL_ALWAYS,           // kAlways_StencilFunc
        GR_GL_NEVER,            // kNever_StencilFunc
        GR_GL_GREATER,          // kGreater_StencilFunc
        GR_GL_GEQUAL,           // kGEqual_StencilFunc
        GR_GL_LESS,             // kLess_StencilFunc
        GR_GL_LEQUAL,           // kLEqual_StencilFunc,
        GR_GL_EQUAL,            // kEqual_StencilFunc,
        GR_GL_NOTEQUAL,         // kNotEqual_StencilFunc,
    };
    GR_STATIC_ASSERT(SK_ARRAY_COUNT(gTable) == kBasicStencilFuncCount);
    GR_STATIC_ASSERT(0 == kAlways_StencilFunc);
    GR_STATIC_ASSERT(1 == kNever_StencilFunc);
    GR_STATIC_ASSERT(2 == kGreater_StencilFunc);
    GR_STATIC_ASSERT(3 == kGEqual_StencilFunc);
    GR_STATIC_ASSERT(4 == kLess_StencilFunc);
    GR_STATIC_ASSERT(5 == kLEqual_StencilFunc);
    GR_STATIC_ASSERT(6 == kEqual_StencilFunc);
    GR_STATIC_ASSERT(7 == kNotEqual_StencilFunc);
    SkASSERT((unsigned) basicFunc < kBasicStencilFuncCount);

    return gTable[basicFunc];
}