s_zoom.c

Mesa is an open-source implementation of the OpenGL specification - a system for rendering interacti

         const GLfloat (*rgba)[4] = (const GLfloat (*)[4]) src;
         GLint i;
         for (i = 0; i < zoomedWidth; i++) {
            GLint j = unzoom_x(ctx->Pixel.ZoomX, imgX, x0 + i) - span->x;
            ASSERT(j >= 0);
            ASSERT(j < span->end);
            COPY_4V(zoomed.array->attribs[FRAG_ATTRIB_COL0][i], rgba[j]);
         }
      }
   }
   else if (format == GL_RGB) {
      if (zoomed.array->ChanType == GL_UNSIGNED_BYTE) {
         const GLubyte (*rgb)[3] = (const GLubyte (*)[3]) src;
         GLint i;
         for (i = 0; i < zoomedWidth; i++) {
            GLint j = unzoom_x(ctx->Pixel.ZoomX, imgX, x0 + i) - span->x;
            ASSERT(j >= 0);
            ASSERT(j < (GLint) span->end);
            zoomed.array->rgba8[i][0] = rgb[j][0];
            zoomed.array->rgba8[i][1] = rgb[j][1];
            zoomed.array->rgba8[i][2] = rgb[j][2];
            zoomed.array->rgba8[i][3] = 0xff;
         }
      }
      else if (zoomed.array->ChanType == GL_UNSIGNED_SHORT) {
         const GLushort (*rgb)[3] = (const GLushort (*)[3]) src;
         GLint i;
         for (i = 0; i < zoomedWidth; i++) {
            GLint j = unzoom_x(ctx->Pixel.ZoomX, imgX, x0 + i) - span->x;
            ASSERT(j >= 0);
            ASSERT(j < (GLint) span->end);
            zoomed.array->rgba16[i][0] = rgb[j][0];
            zoomed.array->rgba16[i][1] = rgb[j][1];
            zoomed.array->rgba16[i][2] = rgb[j][2];
            zoomed.array->rgba16[i][3] = 0xffff;
         }
      }
      else {
         const GLfloat (*rgb)[3] = (const GLfloat (*)[3]) src;
         GLint i;
         for (i = 0; i < zoomedWidth; i++) {
            GLint j = unzoom_x(ctx->Pixel.ZoomX, imgX, x0 + i) - span->x;
            ASSERT(j >= 0);
            ASSERT(j < span->end);
            zoomed.array->attribs[FRAG_ATTRIB_COL0][i][0] = rgb[j][0];
            zoomed.array->attribs[FRAG_ATTRIB_COL0][i][1] = rgb[j][1];
            zoomed.array->attribs[FRAG_ATTRIB_COL0][i][2] = rgb[j][2];
            zoomed.array->attribs[FRAG_ATTRIB_COL0][i][3] = 1.0F;
         }
      }
   }
   else if (format == GL_COLOR_INDEX) {
      const GLuint *indexes = (const GLuint *) src;
      GLint i;
      for (i = 0; i < zoomedWidth; i++) {
         GLint j = unzoom_x(ctx->Pixel.ZoomX, imgX, x0 + i) - span->x;
         ASSERT(j >= 0);
         ASSERT(j < (GLint) span->end);
         zoomed.array->index[i] = indexes[j];
      }
   }
   else if (format == GL_DEPTH_COMPONENT) {
      const GLuint *zValues = (const GLuint *) src;
      GLint i;
      for (i = 0; i < zoomedWidth; i++) {
         GLint j = unzoom_x(ctx->Pixel.ZoomX, imgX, x0 + i) - span->x;
         ASSERT(j >= 0);
         ASSERT(j < (GLint) span->end);
         zoomed.array->z[i] = zValues[j];
      }
      /* Now, fall into either the RGB or COLOR_INDEX path below */
      format = ctx->Visual.rgbMode ? GL_RGBA : GL_COLOR_INDEX;
   }

   /* write the span in rows [r0, r1) */
   if (format == GL_RGBA || format == GL_RGB) {
      /* Writing the span may modify the colors, so make a backup now if we're
       * going to call _swrast_write_zoomed_span() more than once.
       * Also, clipping may change the span end value, so store it as well.
       */
      const GLint end = zoomed.end; /* save */
      GLuint rgbaSave[MAX_WIDTH][4];
      const GLint pixelSize =
         (zoomed.array->ChanType == GL_UNSIGNED_BYTE) ? 4 * sizeof(GLubyte) :
         ((zoomed.array->ChanType == GL_UNSIGNED_SHORT) ? 4 * sizeof(GLushort)
          : 4 * sizeof(GLfloat));
      if (y1 - y0 > 1) {
         MEMCPY(rgbaSave, zoomed.array->rgba, zoomed.end * pixelSize);
      }
      for (zoomed.y = y0; zoomed.y < y1; zoomed.y++) {
         _swrast_write_rgba_span(ctx, &zoomed);
         zoomed.end = end;  /* restore */
         if (y1 - y0 > 1) {
            /* restore the colors */
            MEMCPY(zoomed.array->rgba, rgbaSave, zoomed.end * pixelSize);
         }
      }
   }
   else if (format == GL_COLOR_INDEX) {
      /* use specular color array for temp storage */
      GLuint *indexSave = (GLuint *) zoomed.array->attribs[FRAG_ATTRIB_FOGC];
      const GLint end = zoomed.end; /* save */
      if (y1 - y0 > 1) {
         MEMCPY(indexSave, zoomed.array->index, zoomed.end * sizeof(GLuint));
      }
      for (zoomed.y = y0; zoomed.y < y1; zoomed.y++) {
         _swrast_write_index_span(ctx, &zoomed);
         zoomed.end = end;  /* restore */
         if (y1 - y0 > 1) {
            /* restore the colors */
            MEMCPY(zoomed.array->index, indexSave, zoomed.end * sizeof(GLuint));
         }
      }
   }
}


void
_swrast_write_zoomed_rgba_span(GLcontext *ctx, GLint imgX, GLint imgY,
                               const SWspan *span, const GLvoid *rgba)
{
   zoom_span(ctx, imgX, imgY, span, rgba, GL_RGBA);
}


void
_swrast_write_zoomed_rgb_span(GLcontext *ctx, GLint imgX, GLint imgY,
                              const SWspan *span, const GLvoid *rgb)
{
   zoom_span(ctx, imgX, imgY, span, rgb, GL_RGB);
}


void
_swrast_write_zoomed_index_span(GLcontext *ctx, GLint imgX, GLint imgY,
                                const SWspan *span)
{
   zoom_span(ctx, imgX, imgY, span,
             (const GLvoid *) span->array->index, GL_COLOR_INDEX);
}


void
_swrast_write_zoomed_depth_span(GLcontext *ctx, GLint imgX, GLint imgY,
                                const SWspan *span)
{
   zoom_span(ctx, imgX, imgY, span,
             (const GLvoid *) span->array->z, GL_DEPTH_COMPONENT);
}


/**
 * Zoom/write stencil values.
 * No per-fragment operations are applied.
 */
void
_swrast_write_zoomed_stencil_span(GLcontext *ctx, GLint imgX, GLint imgY,
                                  GLint width, GLint spanX, GLint spanY,
                                  const GLstencil stencil[])
{
   GLstencil zoomedVals[MAX_WIDTH];
   GLint x0, x1, y0, y1, y;
   GLint i, zoomedWidth;

   if (!compute_zoomed_bounds(ctx, imgX, imgY, spanX, spanY, width,
                              &x0, &x1, &y0, &y1)) {
      return;  /* totally clipped */
   }

   zoomedWidth = x1 - x0;
   ASSERT(zoomedWidth > 0);
   ASSERT(zoomedWidth <= MAX_WIDTH);

   /* zoom the span horizontally */
   for (i = 0; i < zoomedWidth; i++) {
      GLint j = unzoom_x(ctx->Pixel.ZoomX, imgX, x0 + i) - spanX;
      ASSERT(j >= 0);
      ASSERT(j < width);
      zoomedVals[i] = stencil[j];
   }

   /* write the zoomed spans */
   for (y = y0; y < y1; y++) {
      _swrast_write_stencil_span(ctx, zoomedWidth, x0, y, zoomedVals);
   }
}


/**
 * Zoom/write z values (16 or 32-bit).
 * No per-fragment operations are applied.
 */
void
_swrast_write_zoomed_z_span(GLcontext *ctx, GLint imgX, GLint imgY,
                            GLint width, GLint spanX, GLint spanY,
                            const GLvoid *z)
{
   struct gl_renderbuffer *rb = ctx->DrawBuffer->_DepthBuffer;
   GLushort zoomedVals16[MAX_WIDTH];
   GLuint zoomedVals32[MAX_WIDTH];
   GLint x0, x1, y0, y1, y;
   GLint i, zoomedWidth;

   if (!compute_zoomed_bounds(ctx, imgX, imgY, spanX, spanY, width,
                              &x0, &x1, &y0, &y1)) {
      return;  /* totally clipped */
   }

   zoomedWidth = x1 - x0;
   ASSERT(zoomedWidth > 0);
   ASSERT(zoomedWidth <= MAX_WIDTH);

   /* zoom the span horizontally */
   if (rb->DataType == GL_UNSIGNED_SHORT) {
      for (i = 0; i < zoomedWidth; i++) {
         GLint j = unzoom_x(ctx->Pixel.ZoomX, imgX, x0 + i) - spanX;
         ASSERT(j >= 0);
         ASSERT(j < width);
         zoomedVals16[i] = ((GLushort *) z)[j];
      }
      z = zoomedVals16;
   }
   else {
      ASSERT(rb->DataType == GL_UNSIGNED_INT);
      for (i = 0; i < zoomedWidth; i++) {
         GLint j = unzoom_x(ctx->Pixel.ZoomX, imgX, x0 + i) - spanX;
         ASSERT(j >= 0);
         ASSERT(j < width);
         zoomedVals32[i] = ((GLuint *) z)[j];
      }
      z = zoomedVals32;
   }

   /* write the zoomed spans */
   for (y = y0; y < y1; y++) {
      rb->PutRow(ctx, rb, zoomedWidth, x0, y, z, NULL);
   }
}