-/* $Id: depth.c,v 1.16 2000/04/04 00:54:23 brianp Exp $ */
+/* $Id: depth.c,v 1.17 2000/04/11 20:42:22 brianp Exp $ */
/*
* Mesa 3-D graphics library
/**********************************************************************/
+/*
+ * Read a span of depth values from the depth buffer.
+ * This function does clipping before calling the device driver function.
+ */
+void
+_mesa_read_depth_span( GLcontext *ctx,
+ GLint n, GLint x, GLint y, GLdepth depth[] )
+{
+ if (y < 0 || y >= ctx->DrawBuffer->Height ||
+ x + (GLint) n <= 0 || x >= ctx->DrawBuffer->Width) {
+ /* span is completely outside framebuffer */
+ GLint i;
+ for (i = 0; i < n; i++)
+ depth[i] = 0;
+ return;
+ }
+
+ if (x < 0) {
+ GLint dx = -x;
+ GLint i;
+ for (i = 0; i < dx; i++)
+ depth[i] = 0;
+ x = 0;
+ n -= dx;
+ depth += dx;
+ }
+ if (x + n > ctx->DrawBuffer->Width) {
+ GLint dx = x + n - ctx->DrawBuffer->Width;
+ GLint i;
+ for (i = 0; i < dx; i++)
+ depth[n - i - 1] = 0;
+ n -= dx;
+ }
+ if (n <= 0) {
+ return;
+ }
+
+ if (ctx->DrawBuffer->DepthBuffer) {
+ /* read from software depth buffer */
+ if (ctx->Visual->DepthBits <= 16) {
+ const GLushort *zptr = Z_ADDRESS16( ctx, x, y );
+ GLuint i;
+ for (i = 0; i < n; i++) {
+ depth[i] = zptr[i];
+ }
+ }
+ else {
+ const GLuint *zptr = Z_ADDRESS32( ctx, x, y );
+ GLuint i;
+ for (i = 0; i < n; i++) {
+ depth[i] = zptr[i];
+ }
+ }
+ }
+ else if (ctx->Driver.ReadDepthSpan) {
+ /* read from hardware depth buffer */
+ (*ctx->Driver.ReadDepthSpan)( ctx, n, x, y, depth );
+ }
+ else {
+ /* no depth buffer */
+ BZERO(depth, n * sizeof(GLfloat));
+ }
+
+}
+
+
+
+
/*
* Return a span of depth values from the depth buffer as floats in [0,1].
* This is used for both hardware and software depth buffers.
* Output: depth - the array of depth values
*/
void
-_mesa_read_depth_span_float( GLcontext* ctx,
- GLuint n, GLint x, GLint y, GLfloat depth[] )
+_mesa_read_depth_span_float( GLcontext *ctx,
+ GLint n, GLint x, GLint y, GLfloat depth[] )
{
const GLfloat scale = 1.0F / ctx->Visual->DepthMaxF;
+ if (y < 0 || y >= ctx->DrawBuffer->Height ||
+ x + (GLint) n <= 0 || x >= ctx->DrawBuffer->Width) {
+ /* span is completely outside framebuffer */
+ GLint i;
+ for (i = 0; i < n; i++)
+ depth[i] = 0.0F;
+ return;
+ }
+
+ if (x < 0) {
+ GLint dx = -x;
+ GLint i;
+ for (i = 0; i < dx; i++)
+ depth[i] = 0.0F;
+ n -= dx;
+ x = 0;
+ }
+ if (x + n > ctx->DrawBuffer->Width) {
+ GLint dx = x + n - ctx->DrawBuffer->Width;
+ GLint i;
+ for (i = 0; i < dx; i++)
+ depth[n - i - 1] = 0.0F;
+ n -= dx;
+ }
+ if (n <= 0) {
+ return;
+ }
+
if (ctx->DrawBuffer->DepthBuffer) {
/* read from software depth buffer */
if (ctx->Visual->DepthBits <= 16) {