The bound range is disconnected from the viewport dimensions. This is
the relevant bit from glViewportArray:
"""
The location of the viewport's bottom left corner, given by (x, y) is
clamped to be within the implementaiton-dependent viewport bounds range.
The viewport bounds range [min, max] can be determined by calling glGet
with argument GL_VIEWPORT_BOUNDS_RANGE. Viewport width and height are
silently clamped to a range that depends on the implementation. To query
this range, call glGet with argument GL_MAX_VIEWPORT_DIMS.
"""
Just set it to +/-16384, as that is the minimum required by
ARB_viewport_array and the value that all current drivers provide.
Signed-off-by: Ilia Mirkin <imir...@alum.mit.edu>
---
src/mesa/state_tracker/st_extensions.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/src/mesa/state_tracker/st_extensions.c
b/src/mesa/state_tracker/st_extensions.c
index 1f391c9..c54b18b 100644
--- a/src/mesa/state_tracker/st_extensions.c
+++ b/src/mesa/state_tracker/st_extensions.c
@@ -783,8 +783,8 @@ void st_init_extensions(struct st_context *st)
if (ctx->API == API_OPENGL_CORE) {
ctx->Const.MaxViewports = screen->get_param(screen,
PIPE_CAP_MAX_VIEWPORTS);
if (ctx->Const.MaxViewports >= 16) {
- ctx->Const.ViewportBounds.Min = -(float)ctx->Const.MaxViewportWidth;
- ctx->Const.ViewportBounds.Max = ctx->Const.MaxViewportWidth;
+ ctx->Const.ViewportBounds.Min = -16384.0;
+ ctx->Const.ViewportBounds.Max = 16384.0;
ctx->Extensions.ARB_viewport_array = GL_TRUE;
}
}
--
1.8.3.2
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