/* * Mesa 3-D graphics library * Version: 7.5 * * Copyright (C) 1999-2008 Brian Paul All Rights Reserved. * Copyright (C) 2009 VMware, Inc. All Rights Reserved. * * Permission is hereby granted, free of charge, to any person obtaining a * copy of this software and associated documentation files (the "Software"), * to deal in the Software without restriction, including without limitation * the rights to use, copy, modify, merge, publish, distribute, sublicense, * and/or sell copies of the Software, and to permit persons to whom the * Software is furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included * in all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL * THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */ /** * \file image.c * Image handling. */ #include "glheader.h" #include "colormac.h" #include "glformats.h" #include "image.h" #include "imports.h" #include "macros.h" #include "mtypes.h" /** * Flip the order of the 2 bytes in each word in the given array. * * \param p array. * \param n number of words. */ void _mesa_swap2( GLushort *p, GLuint n ) { GLuint i; for (i = 0; i < n; i++) { p[i] = (p[i] >> 8) | ((p[i] << 8) & 0xff00); } } /* * Flip the order of the 4 bytes in each word in the given array. */ void _mesa_swap4( GLuint *p, GLuint n ) { GLuint i, a, b; for (i = 0; i < n; i++) { b = p[i]; a = (b >> 24) | ((b >> 8) & 0xff00) | ((b << 8) & 0xff0000) | ((b << 24) & 0xff000000); p[i] = a; } } /** * Return the byte offset of a specific pixel in an image (1D, 2D or 3D). * * Pixel unpacking/packing parameters are observed according to \p packing. * * \param dimensions either 1, 2 or 3 to indicate dimensionality of image * \param packing the pixelstore attributes * \param width the image width * \param height the image height * \param format the pixel format (must be validated beforehand) * \param type the pixel data type (must be validated beforehand) * \param img which image in the volume (0 for 1D or 2D images) * \param row row of pixel in the image (0 for 1D images) * \param column column of pixel in the image * * \return offset of pixel. * * \sa gl_pixelstore_attrib. */ GLintptr _mesa_image_offset( GLuint dimensions, const struct gl_pixelstore_attrib *packing, GLsizei width, GLsizei height, GLenum format, GLenum type, GLint img, GLint row, GLint column ) { GLint alignment; /* 1, 2 or 4 */ GLint pixels_per_row; GLint rows_per_image; GLint skiprows; GLint skippixels; GLint skipimages; /* for 3-D volume images */ GLintptr offset; ASSERT(dimensions >= 1 && dimensions <= 3); alignment = packing->Alignment; if (packing->RowLength > 0) { pixels_per_row = packing->RowLength; } else { pixels_per_row = width; } if (packing->ImageHeight > 0) { rows_per_image = packing->ImageHeight; } else { rows_per_image = height; } skippixels = packing->SkipPixels; /* Note: SKIP_ROWS _is_ used for 1D images */ skiprows = packing->SkipRows; /* Note: SKIP_IMAGES is only used for 3D images */ skipimages = (dimensions == 3) ? packing->SkipImages : 0; if (type == GL_BITMAP) { /* BITMAP data */ GLint bytes_per_row; GLint bytes_per_image; /* components per pixel for color or stencil index: */ const GLint comp_per_pixel = 1; /* The pixel type and format should have been error checked earlier */ assert(format == GL_COLOR_INDEX || format == GL_STENCIL_INDEX); bytes_per_row = alignment * CEILING( comp_per_pixel*pixels_per_row, 8*alignment ); bytes_per_image = bytes_per_row * rows_per_image; offset = (skipimages + img) * bytes_per_image + (skiprows + row) * bytes_per_row + (skippixels + column) / 8; } else { /* Non-BITMAP data */ GLint bytes_per_pixel, bytes_per_row, remainder, bytes_per_image; GLint topOfImage; bytes_per_pixel = _mesa_bytes_per_pixel( format, type ); /* The pixel type and format should have been error checked earlier */ assert(bytes_per_pixel > 0); bytes_per_row = pixels_per_row * bytes_per_pixel; remainder = bytes_per_row % alignment; if (remainder > 0) bytes_per_row += (alignment - remainder); ASSERT(bytes_per_row % alignment == 0); bytes_per_image = bytes_per_row * rows_per_image; if (packing->Invert) { /* set pixel_addr to the last row */ topOfImage = bytes_per_row * (height - 1); bytes_per_row = -bytes_per_row; } else { topOfImage = 0; } /* compute final pixel address */ offset = (skipimages + img) * bytes_per_image + topOfImage + (skiprows + row) * bytes_per_row + (skippixels + column) * bytes_per_pixel; } return offset; } /** * Return the address of a specific pixel in an image (1D, 2D or 3D). * * Pixel unpacking/packing parameters are observed according to \p packing. * * \param dimensions either 1, 2 or 3 to indicate dimensionality of image * \param packing the pixelstore attributes * \param image starting address of image data * \param width the image width * \param height the image height * \param format the pixel format (must be validated beforehand) * \param type the pixel data type (must be validated beforehand) * \param img which image in the volume (0 for 1D or 2D images) * \param row row of pixel in the image (0 for 1D images) * \param column column of pixel in the image * * \return address of pixel. * * \sa gl_pixelstore_attrib. */ GLvoid * _mesa_image_address( GLuint dimensions, const struct gl_pixelstore_attrib *packing, const GLvoid *image, GLsizei width, GLsizei height, GLenum format, GLenum type, GLint img, GLint row, GLint column ) { const GLubyte *addr = (const GLubyte *) image; addr += _mesa_image_offset(dimensions, packing, width, height, format, type, img, row, column); return (GLvoid *) addr; } GLvoid * _mesa_image_address1d( const struct gl_pixelstore_attrib *packing, const GLvoid *image, GLsizei width, GLenum format, GLenum type, GLint column ) { return _mesa_image_address(1, packing, image, width, 1, format, type, 0, 0, column); } GLvoid * _mesa_image_address2d( const struct gl_pixelstore_attrib *packing, const GLvoid *image, GLsizei width, GLsizei height, GLenum format, GLenum type, GLint row, GLint column ) { return _mesa_image_address(2, packing, image, width, height, format, type, 0, row, column); } GLvoid * _mesa_image_address3d( const struct gl_pixelstore_attrib *packing, const GLvoid *image, GLsizei width, GLsizei height, GLenum format, GLenum type, GLint img, GLint row, GLint column ) { return _mesa_image_address(3, packing, image, width, height, format, type, img, row, column); } /** * Compute the stride (in bytes) between image rows. * * \param packing the pixelstore attributes * \param width image width. * \param format pixel format. * \param type pixel data type. * * \return the stride in bytes for the given parameters, or -1 if error */ GLint _mesa_image_row_stride( const struct gl_pixelstore_attrib *packing, GLint width, GLenum format, GLenum type ) { GLint bytesPerRow, remainder; ASSERT(packing); if (type == GL_BITMAP) { if (packing->RowLength == 0) { bytesPerRow = (width + 7) / 8; } else { bytesPerRow = (packing->RowLength + 7) / 8; } } else { /* Non-BITMAP data */ const GLint bytesPerPixel = _mesa_bytes_per_pixel(format, type); if (bytesPerPixel <= 0) return -1; /* error */ if (packing->RowLength == 0) { bytesPerRow = bytesPerPixel * width; } else { bytesPerRow = bytesPerPixel * packing->RowLength; } } remainder = bytesPerRow % packing->Alignment; if (remainder > 0) { bytesPerRow += (packing->Alignment - remainder); } if (packing->Invert) { /* negate the bytes per row (negative row stride) */ bytesPerRow = -bytesPerRow; } return bytesPerRow; } /* * Compute the stride between images in a 3D texture (in bytes) for the given * pixel packing parameters and image width, format and type. */ GLint _mesa_image_image_stride( const struct gl_pixelstore_attrib *packing, GLint width, GLint height, GLenum format, GLenum type ) { GLint bytesPerRow, bytesPerImage, remainder; ASSERT(packing); if (type == GL_BITMAP) { if (packing->RowLength == 0) { bytesPerRow = (width + 7) / 8; } else { bytesPerRow = (packing->RowLength + 7) / 8; } } else { const GLint bytesPerPixel = _mesa_bytes_per_pixel(format, type); if (bytesPerPixel <= 0) return -1; /* error */ if (packing->RowLength == 0) { bytesPerRow = bytesPerPixel * width; } else { bytesPerRow = bytesPerPixel * packing->RowLength; } } remainder = bytesPerRow % packing->Alignment; if (remainder > 0) bytesPerRow += (packing->Alignment - remainder); if (packing->ImageHeight == 0) bytesPerImage = bytesPerRow * height; else bytesPerImage = bytesPerRow * packing->ImageHeight; return bytesPerImage; } /** * "Expand" a bitmap from 1-bit per pixel to 8-bits per pixel. * This is typically used to convert a bitmap into a GLubyte/pixel texture. * "On" bits will set texels to \p onValue. * "Off" bits will not modify texels. * \param width src bitmap width in pixels * \param height src bitmap height in pixels * \param unpack bitmap unpacking state * \param bitmap the src bitmap data * \param destBuffer start of dest buffer * \param destStride row stride in dest buffer * \param onValue if bit is 1, set destBuffer pixel to this value */ void _mesa_expand_bitmap(GLsizei width, GLsizei height, const struct gl_pixelstore_attrib *unpack, const GLubyte *bitmap, GLubyte *destBuffer, GLint destStride, GLubyte onValue) { const GLubyte *srcRow = (const GLubyte *) _mesa_image_address2d(unpack, bitmap, width, height, GL_COLOR_INDEX, GL_BITMAP, 0, 0); const GLint srcStride = _mesa_image_row_stride(unpack, width, GL_COLOR_INDEX, GL_BITMAP); GLint row, col; #define SET_PIXEL(COL, ROW) \ destBuffer[(ROW) * destStride + (COL)] = onValue; for (row = 0; row < height; row++) { const GLubyte *src = srcRow; if (unpack->LsbFirst) { /* Lsb first */ GLubyte mask = 1U << (unpack->SkipPixels & 0x7); for (col = 0; col < width; col++) { if (*src & mask) { SET_PIXEL(col, row); } if (mask == 128U) { src++; mask = 1U; } else { mask = mask << 1; } } /* get ready for next row */ if (mask != 1) src++; } else { /* Msb first */ GLubyte mask = 128U >> (unpack->SkipPixels & 0x7); for (col = 0; col < width; col++) { if (*src & mask) { SET_PIXEL(col, row); } if (mask == 1U) { src++; mask = 128U; } else { mask = mask >> 1; } } /* get ready for next row */ if (mask != 128) src++; } srcRow += srcStride; } /* row */ #undef SET_PIXEL } /** * Convert an array of RGBA colors from one datatype to another. * NOTE: src may equal dst. In that case, we use a temporary buffer. */ void _mesa_convert_colors(GLenum srcType, const GLvoid *src, GLenum dstType, GLvoid *dst, GLuint count, const GLubyte mask[]) { GLuint *tempBuffer; const GLboolean useTemp = (src == dst); tempBuffer = malloc(count * MAX_PIXEL_BYTES); if (!tempBuffer) return; ASSERT(srcType != dstType); switch (srcType) { case GL_UNSIGNED_BYTE: if (dstType == GL_UNSIGNED_SHORT) { const GLubyte (*src1)[4] = (const GLubyte (*)[4]) src; GLushort (*dst2)[4] = (GLushort (*)[4]) (useTemp ? tempBuffer : dst); GLuint i; for (i = 0; i < count; i++) { if (!mask || mask[i]) { dst2[i][RCOMP] = UBYTE_TO_USHORT(src1[i][RCOMP]); dst2[i][GCOMP] = UBYTE_TO_USHORT(src1[i][GCOMP]); dst2[i][BCOMP] = UBYTE_TO_USHORT(src1[i][BCOMP]); dst2[i][ACOMP] = UBYTE_TO_USHORT(src1[i][ACOMP]); } } if (useTemp) memcpy(dst, tempBuffer, count * 4 * sizeof(GLushort)); } else { const GLubyte (*src1)[4] = (const GLubyte (*)[4]) src; GLfloat (*dst4)[4] = (GLfloat (*)[4]) (useTemp ? tempBuffer : dst); GLuint i; ASSERT(dstType == GL_FLOAT); for (i = 0; i < count; i++) { if (!mask || mask[i]) { dst4[i][RCOMP] = UBYTE_TO_FLOAT(src1[i][RCOMP]); dst4[i][GCOMP] = UBYTE_TO_FLOAT(src1[i][GCOMP]); dst4[i][BCOMP] = UBYTE_TO_FLOAT(src1[i][BCOMP]); dst4[i][ACOMP] = UBYTE_TO_FLOAT(src1[i][ACOMP]); } } if (useTemp) memcpy(dst, tempBuffer, count * 4 * sizeof(GLfloat)); } break; case GL_UNSIGNED_SHORT: if (dstType == GL_UNSIGNED_BYTE) { const GLushort (*src2)[4] = (const GLushort (*)[4]) src; GLubyte (*dst1)[4] = (GLubyte (*)[4]) (useTemp ? tempBuffer : dst); GLuint i; for (i = 0; i < count; i++) { if (!mask || mask[i]) { dst1[i][RCOMP] = USHORT_TO_UBYTE(src2[i][RCOMP]); dst1[i][GCOMP] = USHORT_TO_UBYTE(src2[i][GCOMP]); dst1[i][BCOMP] = USHORT_TO_UBYTE(src2[i][BCOMP]); dst1[i][ACOMP] = USHORT_TO_UBYTE(src2[i][ACOMP]); } } if (useTemp) memcpy(dst, tempBuffer, count * 4 * sizeof(GLubyte)); } else { const GLushort (*src2)[4] = (const GLushort (*)[4]) src; GLfloat (*dst4)[4] = (GLfloat (*)[4]) (useTemp ? tempBuffer : dst); GLuint i; ASSERT(dstType == GL_FLOAT); for (i = 0; i < count; i++) { if (!mask || mask[i]) { dst4[i][RCOMP] = USHORT_TO_FLOAT(src2[i][RCOMP]); dst4[i][GCOMP] = USHORT_TO_FLOAT(src2[i][GCOMP]); dst4[i][BCOMP] = USHORT_TO_FLOAT(src2[i][BCOMP]); dst4[i][ACOMP] = USHORT_TO_FLOAT(src2[i][ACOMP]); } } if (useTemp) memcpy(dst, tempBuffer, count * 4 * sizeof(GLfloat)); } break; case GL_FLOAT: if (dstType == GL_UNSIGNED_BYTE) { const GLfloat (*src4)[4] = (const GLfloat (*)[4]) src; GLubyte (*dst1)[4] = (GLubyte (*)[4]) (useTemp ? tempBuffer : dst); GLuint i; for (i = 0; i < count; i++) { if (!mask || mask[i]) _mesa_unclamped_float_rgba_to_ubyte(dst1[i], src4[i]); } if (useTemp) memcpy(dst, tempBuffer, count * 4 * sizeof(GLubyte)); } else { const GLfloat (*src4)[4] = (const GLfloat (*)[4]) src; GLushort (*dst2)[4] = (GLushort (*)[4]) (useTemp ? tempBuffer : dst); GLuint i; ASSERT(dstType == GL_UNSIGNED_SHORT); for (i = 0; i < count; i++) { if (!mask || mask[i]) { UNCLAMPED_FLOAT_TO_USHORT(dst2[i][RCOMP], src4[i][RCOMP]); UNCLAMPED_FLOAT_TO_USHORT(dst2[i][GCOMP], src4[i][GCOMP]); UNCLAMPED_FLOAT_TO_USHORT(dst2[i][BCOMP], src4[i][BCOMP]); UNCLAMPED_FLOAT_TO_USHORT(dst2[i][ACOMP], src4[i][ACOMP]); } } if (useTemp) memcpy(dst, tempBuffer, count * 4 * sizeof(GLushort)); } break; default: _mesa_problem(NULL, "Invalid datatype in _mesa_convert_colors"); } free(tempBuffer); } /** * Perform basic clipping for glDrawPixels. The image's position and size * and the unpack SkipPixels and SkipRows are adjusted so that the image * region is entirely within the window and scissor bounds. * NOTE: this will only work when glPixelZoom is (1, 1) or (1, -1). * If Pixel.ZoomY is -1, *destY will be changed to be the first row which * we'll actually write. Beforehand, *destY-1 is the first drawing row. * * \return GL_TRUE if image is ready for drawing or * GL_FALSE if image was completely clipped away (draw nothing) */ GLboolean _mesa_clip_drawpixels(const struct gl_context *ctx, GLint *destX, GLint *destY, GLsizei *width, GLsizei *height, struct gl_pixelstore_attrib *unpack) { const struct gl_framebuffer *buffer = ctx->DrawBuffer; if (unpack->RowLength == 0) { unpack->RowLength = *width; } ASSERT(ctx->Pixel.ZoomX == 1.0F); ASSERT(ctx->Pixel.ZoomY == 1.0F || ctx->Pixel.ZoomY == -1.0F); /* left clipping */ if (*destX < buffer->_Xmin) { unpack->SkipPixels += (buffer->_Xmin - *destX); *width -= (buffer->_Xmin - *destX); *destX = buffer->_Xmin; } /* right clipping */ if (*destX + *width > buffer->_Xmax) *width -= (*destX + *width - buffer->_Xmax); if (*width <= 0) return GL_FALSE; if (ctx->Pixel.ZoomY == 1.0F) { /* bottom clipping */ if (*destY < buffer->_Ymin) { unpack->SkipRows += (buffer->_Ymin - *destY); *height -= (buffer->_Ymin - *destY); *destY = buffer->_Ymin; } /* top clipping */ if (*destY + *height > buffer->_Ymax) *height -= (*destY + *height - buffer->_Ymax); } else { /* upside down */ /* top clipping */ if (*destY > buffer->_Ymax) { unpack->SkipRows += (*destY - buffer->_Ymax); *height -= (*destY - buffer->_Ymax); *destY = buffer->_Ymax; } /* bottom clipping */ if (*destY - *height < buffer->_Ymin) *height -= (buffer->_Ymin - (*destY - *height)); /* adjust destY so it's the first row to write to */ (*destY)--; } if (*height <= 0) return GL_FALSE; return GL_TRUE; } /** * Perform clipping for glReadPixels. The image's window position * and size, and the pack skipPixels, skipRows and rowLength are adjusted * so that the image region is entirely within the window bounds. * Note: this is different from _mesa_clip_drawpixels() in that the * scissor box is ignored, and we use the bounds of the current readbuffer * surface. * * \return GL_TRUE if region to read is in bounds * GL_FALSE if region is completely out of bounds (nothing to read) */ GLboolean _mesa_clip_readpixels(const struct gl_context *ctx, GLint *srcX, GLint *srcY, GLsizei *width, GLsizei *height, struct gl_pixelstore_attrib *pack) { const struct gl_framebuffer *buffer = ctx->ReadBuffer; if (pack->RowLength == 0) { pack->RowLength = *width; } /* left clipping */ if (*srcX < 0) { pack->SkipPixels += (0 - *srcX); *width -= (0 - *srcX); *srcX = 0; } /* right clipping */ if (*srcX + *width > (GLsizei) buffer->Width) *width -= (*srcX + *width - buffer->Width); if (*width <= 0) return GL_FALSE; /* bottom clipping */ if (*srcY < 0) { pack->SkipRows += (0 - *srcY); *height -= (0 - *srcY); *srcY = 0; } /* top clipping */ if (*srcY + *height > (GLsizei) buffer->Height) *height -= (*srcY + *height - buffer->Height); if (*height <= 0) return GL_FALSE; return GL_TRUE; } /** * Do clipping for a glCopyTexSubImage call. * The framebuffer source region might extend outside the framebuffer * bounds. Clip the source region against the framebuffer bounds and * adjust the texture/dest position and size accordingly. * * \return GL_FALSE if region is totally clipped, GL_TRUE otherwise. */ GLboolean _mesa_clip_copytexsubimage(const struct gl_context *ctx, GLint *destX, GLint *destY, GLint *srcX, GLint *srcY, GLsizei *width, GLsizei *height) { const struct gl_framebuffer *fb = ctx->ReadBuffer; const GLint srcX0 = *srcX, srcY0 = *srcY; if (_mesa_clip_to_region(0, 0, fb->Width, fb->Height, srcX, srcY, width, height)) { *destX = *destX + *srcX - srcX0; *destY = *destY + *srcY - srcY0; return GL_TRUE; } else { return GL_FALSE; } } /** * Clip the rectangle defined by (x, y, width, height) against the bounds * specified by [xmin, xmax) and [ymin, ymax). * \return GL_FALSE if rect is totally clipped, GL_TRUE otherwise. */ GLboolean _mesa_clip_to_region(GLint xmin, GLint ymin, GLint xmax, GLint ymax, GLint *x, GLint *y, GLsizei *width, GLsizei *height ) { /* left clipping */ if (*x < xmin) { *width -= (xmin - *x); *x = xmin; } /* right clipping */ if (*x + *width > xmax) *width -= (*x + *width - xmax); if (*width <= 0) return GL_FALSE; /* bottom (or top) clipping */ if (*y < ymin) { *height -= (ymin - *y); *y = ymin; } /* top (or bottom) clipping */ if (*y + *height > ymax) *height -= (*y + *height - ymax); if (*height <= 0) return GL_FALSE; return GL_TRUE; } /** * Clip dst coords against Xmax (or Ymax). */ static inline void clip_right_or_top(GLint *srcX0, GLint *srcX1, GLint *dstX0, GLint *dstX1, GLint maxValue) { GLfloat t, bias; if (*dstX1 > maxValue) { /* X1 outside right edge */ ASSERT(*dstX0 < maxValue); /* X0 should be inside right edge */ t = (GLfloat) (maxValue - *dstX0) / (GLfloat) (*dstX1 - *dstX0); /* chop off [t, 1] part */ ASSERT(t >= 0.0 && t <= 1.0); *dstX1 = maxValue; bias = (*srcX0 < *srcX1) ? 0.5F : -0.5F; *srcX1 = *srcX0 + (GLint) (t * (*srcX1 - *srcX0) + bias); } else if (*dstX0 > maxValue) { /* X0 outside right edge */ ASSERT(*dstX1 < maxValue); /* X1 should be inside right edge */ t = (GLfloat) (maxValue - *dstX1) / (GLfloat) (*dstX0 - *dstX1); /* chop off [t, 1] part */ ASSERT(t >= 0.0 && t <= 1.0); *dstX0 = maxValue; bias = (*srcX0 < *srcX1) ? -0.5F : 0.5F; *srcX0 = *srcX1 + (GLint) (t * (*srcX0 - *srcX1) + bias); } } /** * Clip dst coords against Xmin (or Ymin). */ static inline void clip_left_or_bottom(GLint *srcX0, GLint *srcX1, GLint *dstX0, GLint *dstX1, GLint minValue) { GLfloat t, bias; if (*dstX0 < minValue) { /* X0 outside left edge */ ASSERT(*dstX1 > minValue); /* X1 should be inside left edge */ t = (GLfloat) (minValue - *dstX0) / (GLfloat) (*dstX1 - *dstX0); /* chop off [0, t] part */ ASSERT(t >= 0.0 && t <= 1.0); *dstX0 = minValue; bias = (*srcX0 < *srcX1) ? 0.5F : -0.5F; *srcX0 = *srcX0 + (GLint) (t * (*srcX1 - *srcX0) + bias); } else if (*dstX1 < minValue) { /* X1 outside left edge */ ASSERT(*dstX0 > minValue); /* X0 should be inside left edge */ t = (GLfloat) (minValue - *dstX1) / (GLfloat) (*dstX0 - *dstX1); /* chop off [0, t] part */ ASSERT(t >= 0.0 && t <= 1.0); *dstX1 = minValue; bias = (*srcX0 < *srcX1) ? -0.5F : 0.5F; *srcX1 = *srcX1 + (GLint) (t * (*srcX0 - *srcX1) + bias); } } /** * Do clipping of blit src/dest rectangles. * The dest rect is clipped against both the buffer bounds and scissor bounds. * The src rect is just clipped against the buffer bounds. * * When either the src or dest rect is clipped, the other is also clipped * proportionately! * * Note that X0 need not be less than X1 (same for Y) for either the source * and dest rects. That makes the clipping a little trickier. * * \return GL_TRUE if anything is left to draw, GL_FALSE if totally clipped */ GLboolean _mesa_clip_blit(struct gl_context *ctx, GLint *srcX0, GLint *srcY0, GLint *srcX1, GLint *srcY1, GLint *dstX0, GLint *dstY0, GLint *dstX1, GLint *dstY1) { const GLint srcXmin = 0; const GLint srcXmax = ctx->ReadBuffer->Width; const GLint srcYmin = 0; const GLint srcYmax = ctx->ReadBuffer->Height; /* these include scissor bounds */ const GLint dstXmin = ctx->DrawBuffer->_Xmin; const GLint dstXmax = ctx->DrawBuffer->_Xmax; const GLint dstYmin = ctx->DrawBuffer->_Ymin; const GLint dstYmax = ctx->DrawBuffer->_Ymax; /* printf("PreClipX: src: %d .. %d dst: %d .. %d\n", *srcX0, *srcX1, *dstX0, *dstX1); printf("PreClipY: src: %d .. %d dst: %d .. %d\n", *srcY0, *srcY1, *dstY0, *dstY1); */ /* trivial rejection tests */ if (*dstX0 == *dstX1) return GL_FALSE; /* no width */ if (*dstX0 <= dstXmin && *dstX1 <= dstXmin) return GL_FALSE; /* totally out (left) of bounds */ if (*dstX0 >= dstXmax && *dstX1 >= dstXmax) return GL_FALSE; /* totally out (right) of bounds */ if (*dstY0 == *dstY1) return GL_FALSE; if (*dstY0 <= dstYmin && *dstY1 <= dstYmin) return GL_FALSE; if (*dstY0 >= dstYmax && *dstY1 >= dstYmax) return GL_FALSE; if (*srcX0 == *srcX1) return GL_FALSE; if (*srcX0 <= srcXmin && *srcX1 <= srcXmin) return GL_FALSE; if (*srcX0 >= srcXmax && *srcX1 >= srcXmax) return GL_FALSE; if (*srcY0 == *srcY1) return GL_FALSE; if (*srcY0 <= srcYmin && *srcY1 <= srcYmin) return GL_FALSE; if (*srcY0 >= srcYmax && *srcY1 >= srcYmax) return GL_FALSE; /* * dest clip */ clip_right_or_top(srcX0, srcX1, dstX0, dstX1, dstXmax); clip_right_or_top(srcY0, srcY1, dstY0, dstY1, dstYmax); clip_left_or_bottom(srcX0, srcX1, dstX0, dstX1, dstXmin); clip_left_or_bottom(srcY0, srcY1, dstY0, dstY1, dstYmin); /* * src clip (just swap src/dst values from above) */ clip_right_or_top(dstX0, dstX1, srcX0, srcX1, srcXmax); clip_right_or_top(dstY0, dstY1, srcY0, srcY1, srcYmax); clip_left_or_bottom(dstX0, dstX1, srcX0, srcX1, srcXmin); clip_left_or_bottom(dstY0, dstY1, srcY0, srcY1, srcYmin); /* printf("PostClipX: src: %d .. %d dst: %d .. %d\n", *srcX0, *srcX1, *dstX0, *dstX1); printf("PostClipY: src: %d .. %d dst: %d .. %d\n", *srcY0, *srcY1, *dstY0, *dstY1); */ ASSERT(*dstX0 >= dstXmin); ASSERT(*dstX0 <= dstXmax); ASSERT(*dstX1 >= dstXmin); ASSERT(*dstX1 <= dstXmax); ASSERT(*dstY0 >= dstYmin); ASSERT(*dstY0 <= dstYmax); ASSERT(*dstY1 >= dstYmin); ASSERT(*dstY1 <= dstYmax); ASSERT(*srcX0 >= srcXmin); ASSERT(*srcX0 <= srcXmax); ASSERT(*srcX1 >= srcXmin); ASSERT(*srcX1 <= srcXmax); ASSERT(*srcY0 >= srcYmin); ASSERT(*srcY0 <= srcYmax); ASSERT(*srcY1 >= srcYmin); ASSERT(*srcY1 <= srcYmax); return GL_TRUE; }