On 01/10/2014 05:40 PM, Ian Romanick wrote:
> From: Ian Romanick <ian.d.roman...@intel.com>
>
> Drivers that currently use _Xmin and friends to set their scissor
> rectangle will need to use this code directly once they are updated for
> GL_ARB_viewport_array.
>
> Signed-off-by: Ian Romanick <ian.d.roman...@intel.com>
> ---
> src/mesa/main/framebuffer.c | 85
> +++++++++++++++++++++++++++++----------------
> src/mesa/main/framebuffer.h | 5 +++
> 2 files changed, 61 insertions(+), 29 deletions(-)
>
> diff --git a/src/mesa/main/framebuffer.c b/src/mesa/main/framebuffer.c
> index f14f7a4..04b9a2b 100644
> --- a/src/mesa/main/framebuffer.c
> +++ b/src/mesa/main/framebuffer.c
> @@ -357,6 +357,56 @@ update_framebuffer_size(struct gl_context *ctx, struct
> gl_framebuffer *fb)
>
>
> /**
> + * Calculate the inclusive bounding box for the scissor of a specific
> viewport
> + *
> + * \param ctx GL context.
> + * \param buffer Framebuffer to be checked against
> + * \param idx Index of the desired viewport
> + * \param bbox Bounding box for the scissored viewport. Stored as xmin,
> + * xmax, ymin, ymax.
> + *
> + * \warning This function assumes that the framebuffer dimensions are up to
> + * date (e.g., update_framebuffer_size has been recently called on \c
> buffer).
> + *
> + * \sa _mesa_clip_to_region
> + */
> +void
> +_mesa_scissor_bounding_box(const struct gl_context *ctx,
> + const struct gl_framebuffer *buffer,
> + unsigned idx, int *bbox)
> +{
> + bbox[0] = 0;
> + bbox[2] = 0;
> + bbox[1] = buffer->Width;
> + bbox[3] = buffer->Height;
> +
> + if ((ctx->Scissor.EnableFlags >> idx) & 1) {
Again, I'd prefer:
if (ctx->Scissor.EnableFlags & (1 << idx)) {
> + if (ctx->Scissor.ScissorArray[idx].X > bbox[0]) {
> + bbox[0] = ctx->Scissor.ScissorArray[idx].X;
> + }
> + if (ctx->Scissor.ScissorArray[idx].Y > bbox[2]) {
> + bbox[2] = ctx->Scissor.ScissorArray[idx].Y;
> + }
> + if (ctx->Scissor.ScissorArray[idx].X +
> ctx->Scissor.ScissorArray[idx].Width < bbox[1]) {
> + bbox[1] = ctx->Scissor.ScissorArray[idx].X +
> ctx->Scissor.ScissorArray[idx].Width;
> + }
> + if (ctx->Scissor.ScissorArray[idx].Y +
> ctx->Scissor.ScissorArray[idx].Height < bbox[3]) {
> + bbox[3] = ctx->Scissor.ScissorArray[idx].Y +
> ctx->Scissor.ScissorArray[idx].Height;
> + }
Mixed spaces and tabs here - we just want spaces.
> + /* finally, check for empty region */
> + if (bbox[0] > bbox[1]) {
> + bbox[0] = bbox[1];
> + }
> + if (bbox[2] > bbox[3]) {
> + bbox[2] = bbox[3];
> + }
> + }
> +
> + ASSERT(bbox[0] <= bbox[1]);
> + ASSERT(bbox[2] <= bbox[3]);
You may as well make these assert() instead of ASSERT(). I won't be a
stickler about it though.
> +}
> +
> +/**
> * Update the context's current drawing buffer's Xmin, Xmax, Ymin, Ymax
> fields.
> * These values are computed from the buffer's width and height and
> * the scissor box, if it's enabled.
> @@ -366,6 +416,7 @@ void
> _mesa_update_draw_buffer_bounds(struct gl_context *ctx)
> {
> struct gl_framebuffer *buffer = ctx->DrawBuffer;
> + int bbox[4];
>
> if (!buffer)
> return;
> @@ -375,36 +426,12 @@ _mesa_update_draw_buffer_bounds(struct gl_context *ctx)
> update_framebuffer_size(ctx, buffer);
> }
>
> - buffer->_Xmin = 0;
> - buffer->_Ymin = 0;
> - buffer->_Xmax = buffer->Width;
> - buffer->_Ymax = buffer->Height;
> -
> /* Default to the first scissor as that's always valid */
> - if (ctx->Scissor.EnableFlags & 1) {
> - if (ctx->Scissor.ScissorArray[0].X > buffer->_Xmin) {
> - buffer->_Xmin = ctx->Scissor.ScissorArray[0].X;
> - }
> - if (ctx->Scissor.ScissorArray[0].Y > buffer->_Ymin) {
> - buffer->_Ymin = ctx->Scissor.ScissorArray[0].Y;
> - }
> - if (ctx->Scissor.ScissorArray[0].X +
> ctx->Scissor.ScissorArray[0].Width < buffer->_Xmax) {
> - buffer->_Xmax = ctx->Scissor.ScissorArray[0].X +
> ctx->Scissor.ScissorArray[0].Width;
> - }
> - if (ctx->Scissor.ScissorArray[0].Y +
> ctx->Scissor.ScissorArray[0].Height < buffer->_Ymax) {
> - buffer->_Ymax = ctx->Scissor.ScissorArray[0].Y +
> ctx->Scissor.ScissorArray[0].Height;
> - }
> - /* finally, check for empty region */
> - if (buffer->_Xmin > buffer->_Xmax) {
> - buffer->_Xmin = buffer->_Xmax;
> - }
> - if (buffer->_Ymin > buffer->_Ymax) {
> - buffer->_Ymin = buffer->_Ymax;
> - }
> - }
> -
> - ASSERT(buffer->_Xmin <= buffer->_Xmax);
> - ASSERT(buffer->_Ymin <= buffer->_Ymax);
> + _mesa_scissor_bounding_box(ctx, buffer, 0, bbox);
> + buffer->_Xmin = bbox[0];
> + buffer->_Ymin = bbox[2];
> + buffer->_Xmax = bbox[1];
> + buffer->_Ymax = bbox[3];
> }
>
>
> diff --git a/src/mesa/main/framebuffer.h b/src/mesa/main/framebuffer.h
> index 2645664..a427421 100644
> --- a/src/mesa/main/framebuffer.h
> +++ b/src/mesa/main/framebuffer.h
> @@ -71,6 +71,11 @@ _mesa_resize_framebuffer(struct gl_context *ctx, struct
> gl_framebuffer *fb,
> extern void
> _mesa_resizebuffers( struct gl_context *ctx );
>
> +extern void
> +_mesa_scissor_bounding_box(const struct gl_context *ctx,
> + const struct gl_framebuffer *buffer,
> + unsigned idx, int *bbox);
> +
> extern void
> _mesa_update_draw_buffer_bounds(struct gl_context *ctx);
>
>
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