SDL/src/video/SDL_fillrect.c

/*
  Simple DirectMedia Layer
  Copyright (C) 1997-2026 Sam Lantinga <slouken@libsdl.org>

  This software is provided 'as-is', without any express or implied
  warranty.  In no event will the authors be held liable for any damages
  arising from the use of this software.

  Permission is granted to anyone to use this software for any purpose,
  including commercial applications, and to alter it and redistribute it
  freely, subject to the following restrictions:

  1. The origin of this software must not be misrepresented; you must not
     claim that you wrote the original software. If you use this software
     in a product, an acknowledgment in the product documentation would be
     appreciated but is not required.
  2. Altered source versions must be plainly marked as such, and must not be
     misrepresented as being the original software.
  3. This notice may not be removed or altered from any source distribution.
*/
#include "SDL_internal.h"

#include "SDL_surface_c.h"

#ifdef SDL_SSE_INTRINSICS
/* *INDENT-OFF* */ // clang-format off

#if defined(_MSC_VER) && !defined(__clang__)
#define SSE_BEGIN \
    __m128 c128; \
    c128.m128_u32[0] = color; \
    c128.m128_u32[1] = color; \
    c128.m128_u32[2] = color; \
    c128.m128_u32[3] = color
#else
#define SSE_BEGIN \
    __m128 c128; \
    DECLARE_ALIGNED(Uint32, cccc[4], 16); \
    cccc[0] = color; \
    cccc[1] = color; \
    cccc[2] = color; \
    cccc[3] = color; \
    c128 = *(__m128 *)cccc
#endif

#define SSE_WORK \
    for (i = n / 64; i--;) { \
        _mm_stream_ps((float *)(p+0), c128); \
        _mm_stream_ps((float *)(p+16), c128); \
        _mm_stream_ps((float *)(p+32), c128); \
        _mm_stream_ps((float *)(p+48), c128); \
        p += 64; \
    }

#define SSE_END

#define DEFINE_SSE_FILLRECT(bpp, type) \
static void SDL_TARGETING("sse") SDL_FillSurfaceRect##bpp##SSE(Uint8 *pixels, int pitch, Uint32 color, int w, int h) \
{ \
    int i, n; \
    Uint8 *p = NULL; \
  \
    /* If the number of bytes per row is equal to the pitch, treat */ \
    /* all rows as one long continuous row (for better performance) */ \
    if ((w) * (bpp) == pitch) { \
        w = w * h; \
        h = 1; \
    } \
 \
    SSE_BEGIN; \
 \
    while (h--) { \
        n = (w) * (bpp); \
        p = pixels; \
 \
        if (n > 63) { \
            int adjust = 16 - ((uintptr_t)p & 15); \
            if (adjust < 16) { \
                n -= adjust; \
                adjust /= (bpp); \
                while (adjust--) { \
                    *((type *)p) = (type)color; \
                    p += (bpp); \
                } \
            } \
            SSE_WORK; \
        } \
        if (n & 63) { \
            int remainder = (n & 63); \
            remainder /= (bpp); \
            while (remainder--) { \
                *((type *)p) = (type)color; \
                p += (bpp); \
            } \
        } \
        pixels += pitch; \
    } \
 \
    SSE_END; \
}

static void SDL_TARGETING("sse") SDL_FillSurfaceRect1SSE(Uint8 *pixels, int pitch, Uint32 color, int w, int h)
{
    int i, n;

    SSE_BEGIN;
    while (h--) {
        Uint8 *p = pixels;
        n = w;

        if (n > 63) {
            int adjust = 16 - ((uintptr_t)p & 15);
            if (adjust) {
                n -= adjust;
                SDL_memset(p, color, adjust);
                p += adjust;
            }
            SSE_WORK;
        }
        if (n & 63) {
            int remainder = (n & 63);
            SDL_memset(p, color, remainder);
        }
        pixels += pitch;
    }

    SSE_END;
}
// DEFINE_SSE_FILLRECT(1, Uint8)
DEFINE_SSE_FILLRECT(2, Uint16)
DEFINE_SSE_FILLRECT(4, Uint32)

/* *INDENT-ON* */ // clang-format on
#endif            // __SSE__

#ifdef SDL_LSX_INTRINSICS
/* *INDENT-OFF* */ // clang-format off

#define LSX_BEGIN __m128i c128 = __lsx_vreplgr2vr_w(color);

#define LSX_WORK \
    for (i = n / 64; i--;) { \
        __lsx_vst(c128, p, 0); \
        __lsx_vst(c128, p, 16); \
        __lsx_vst(c128, p, 32); \
        __lsx_vst(c128, p, 48); \
        p += 64; \
    }

#define DEFINE_LSX_FILLRECT(bpp, type) \
static void SDL_TARGETING("lsx") SDL_FillSurfaceRect##bpp##LSX(Uint8 *pixels, int pitch, Uint32 color, int w, int h) \
{ \
    int i, n; \
    Uint8 *p = NULL; \
  \
    /* If the number of bytes per row is equal to the pitch, treat */ \
    /* all rows as one long continuous row (for better performance) */ \
    if ((w) * (bpp) == pitch) { \
        w = w * h; \
        h = 1; \
    } \
 \
    LSX_BEGIN; \
 \
    while (h--) { \
        n = (w) * (bpp); \
        p = pixels; \
 \
        if (n > 63) { \
            int adjust = 16 - ((uintptr_t)p & 15); \
            if (adjust < 16) { \
                n -= adjust; \
                adjust /= (bpp); \
                while (adjust--) { \
                    *((type *)p) = (type)color; \
                    p += (bpp); \
                } \
            } \
            LSX_WORK; \
        } \
        if (n & 63) { \
            int remainder = (n & 63); \
            remainder /= (bpp); \
            while (remainder--) { \
                *((type *)p) = (type)color; \
                p += (bpp); \
            } \
        } \
        pixels += pitch; \
    } \
 \
}

DEFINE_LSX_FILLRECT(4, Uint32)

/* *INDENT-ON* */ // clang-format on
#endif /* __LSX__ */

static void SDL_FillSurfaceRect1(Uint8 *pixels, int pitch, Uint32 color, int w, int h)
{
    int n;
    Uint8 *p = NULL;

    while (h--) {
        n = w;
        p = pixels;

        if (n > 3) {
            switch ((uintptr_t)p & 3) {
            case 1:
                *p++ = (Uint8)color;
                --n;
                SDL_FALLTHROUGH;
            case 2:
                *p++ = (Uint8)color;
                --n;
                SDL_FALLTHROUGH;
            case 3:
                *p++ = (Uint8)color;
                --n;
            }
            SDL_memset4(p, color, (n >> 2));
        }
        if (n & 3) {
            p += (n & ~3);
            switch (n & 3) {
            case 3:
                *p++ = (Uint8)color;
                SDL_FALLTHROUGH;
            case 2:
                *p++ = (Uint8)color;
                SDL_FALLTHROUGH;
            case 1:
                *p++ = (Uint8)color;
            }
        }
        pixels += pitch;
    }
}

static void SDL_FillSurfaceRect2(Uint8 *pixels, int pitch, Uint32 color, int w, int h)
{
    int n;
    Uint16 *p = NULL;

    while (h--) {
        n = w;
        p = (Uint16 *)pixels;

        if (n > 1) {
            if ((uintptr_t)p & 2) {
                *p++ = (Uint16)color;
                --n;
            }
            SDL_memset4(p, color, (n >> 1));
        }
        if (n & 1) {
            p[n - 1] = (Uint16)color;
        }
        pixels += pitch;
    }
}

static void SDL_FillSurfaceRect3(Uint8 *pixels, int pitch, Uint32 color, int w, int h)
{
#if SDL_BYTEORDER == SDL_LIL_ENDIAN
    Uint8 b1 = (Uint8)(color & 0xFF);
    Uint8 b2 = (Uint8)((color >> 8) & 0xFF);
    Uint8 b3 = (Uint8)((color >> 16) & 0xFF);
#elif SDL_BYTEORDER == SDL_BIG_ENDIAN
    Uint8 b1 = (Uint8)((color >> 16) & 0xFF);
    Uint8 b2 = (Uint8)((color >> 8) & 0xFF);
    Uint8 b3 = (Uint8)(color & 0xFF);
#endif
    int n;
    Uint8 *p = NULL;

    while (h--) {
        n = w;
        p = pixels;

        while (n--) {
            *p++ = b1;
            *p++ = b2;
            *p++ = b3;
        }
        pixels += pitch;
    }
}

static void SDL_FillSurfaceRect4(Uint8 *pixels, int pitch, Uint32 color, int w, int h)
{
    while (h--) {
        SDL_memset4(pixels, color, w);
        pixels += pitch;
    }
}

/*
 * This function performs a fast fill of the given rectangle with 'color'
 */
bool SDL_FillSurfaceRect(SDL_Surface *dst, const SDL_Rect *rect, Uint32 color)
{
    CHECK_PARAM(!SDL_SurfaceValid(dst)) {
        return SDL_InvalidParamError("SDL_FillSurfaceRect(): dst");
    }

    // If 'rect' == NULL, then fill the whole surface
    if (!rect) {
        rect = &dst->clip_rect;
        // Don't attempt to fill if the surface's clip_rect is empty
        if (SDL_RectEmpty(rect)) {
            return true;
        }
    }

    return SDL_FillSurfaceRects(dst, rect, 1, color);
}

bool SDL_FillSurfaceRects(SDL_Surface *dst, const SDL_Rect *rects, int count, Uint32 color)
{
    SDL_Rect clipped;
    Uint8 *pixels;
    const SDL_Rect *rect;
    void (*fill_function)(Uint8 * pixels, int pitch, Uint32 color, int w, int h) = NULL;
    int i;

    CHECK_PARAM(!SDL_SurfaceValid(dst)) {
        return SDL_InvalidParamError("SDL_FillSurfaceRects(): dst");
    }

    CHECK_PARAM(!rects) {
        return SDL_InvalidParamError("SDL_FillSurfaceRects(): rects");
    }

    if (!dst->pixels && SDL_MUSTLOCK(dst)) {
        return SDL_SetError("SDL_FillSurfaceRects(): You must lock the surface");
    }

    // Nothing to do
    if (dst->w == 0 || dst->h == 0 || !dst->pixels) {
        return true;
    }

    /* This function doesn't usually work on surfaces < 8 bpp
     * Except: support for 4bits, when filling full size.
     */
    if (SDL_BITSPERPIXEL(dst->format) < 8) {
        if (count == 1) {
            const SDL_Rect *r = &rects[0];
            if (r->x == 0 && r->y == 0 && r->w == dst->w && r->h == dst->h) {
                if (SDL_BITSPERPIXEL(dst->format) == 4) {
                    Uint8 b = (((Uint8)color << 4) | (Uint8)color);
                    SDL_memset(dst->pixels, b, (size_t)dst->h * dst->pitch);
                    return true;
                }
            }
        }
        return SDL_SetError("SDL_FillSurfaceRects(): Unsupported surface format");
    }

    if (fill_function == NULL) {
        switch (SDL_BYTESPERPIXEL(dst->format)) {
        case 1:
        {
            color |= (color << 8);
            color |= (color << 16);
#ifdef SDL_SSE_INTRINSICS
            if (SDL_HasSSE()) {
                fill_function = SDL_FillSurfaceRect1SSE;
                break;
            }
#endif
            fill_function = SDL_FillSurfaceRect1;
            break;
        }

        case 2:
        {
            color |= (color << 16);
#ifdef SDL_SSE_INTRINSICS
            if (SDL_HasSSE()) {
                fill_function = SDL_FillSurfaceRect2SSE;
                break;
            }
#endif
            fill_function = SDL_FillSurfaceRect2;
            break;
        }

        case 3:
            // 24-bit RGB is a slow path, at least for now.
            {
                fill_function = SDL_FillSurfaceRect3;
                break;
            }

        case 4:
        {
#ifdef SDL_SSE_INTRINSICS
            if (SDL_HasSSE()) {
                fill_function = SDL_FillSurfaceRect4SSE;
                break;
            }
#endif
#ifdef SDL_LSX_INTRINSICS
            if (SDL_HasLSX()) {
                fill_function = SDL_FillSurfaceRect4LSX;
                break;
            }
#endif
            fill_function = SDL_FillSurfaceRect4;
            break;
        }

        default:
            return SDL_SetError("Unsupported pixel format");
        }
    }

    for (i = 0; i < count; ++i) {
        rect = &rects[i];
        // Perform clipping
        if (!SDL_GetRectIntersection(rect, &dst->clip_rect, &clipped)) {
            continue;
        }
        rect = &clipped;

        pixels = (Uint8 *)dst->pixels + rect->y * dst->pitch +
                 rect->x * SDL_BYTESPERPIXEL(dst->format);

        fill_function(pixels, dst->pitch, color, rect->w, rect->h);
    }

    // We're done!
    return true;
}