[Bf-blender-cvs] [721a19d2b8a] blender2.8: GPU: Add safety check for max line width

[Clément Foucault]

Commit: 721a19d2b8a7784c48c753d57dfbf984524a54de
Author: Clément Foucault
Date:   Fri Nov 2 14:58:49 2018 +0100
Branches: blender2.8
https://developer.blender.org/rB721a19d2b8a7784c48c753d57dfbf984524a54de

GPU: Add safety check for max line width

On some platform does not support line width > 1.0 and can even throw and
error. Better check an at least display something rather than no lines at
all.

===================================================================

M	source/blender/gpu/GPU_extensions.h
M	source/blender/gpu/intern/gpu_extensions.c
M	source/blender/gpu/intern/gpu_state.c

===================================================================

diff --git a/source/blender/gpu/GPU_extensions.h b/source/blender/gpu/GPU_extensions.h
index 805023e31df..07d8a5f8c8b 100644
--- a/source/blender/gpu/GPU_extensions.h
+++ b/source/blender/gpu/GPU_extensions.h
@@ -49,6 +49,7 @@ int GPU_max_color_texture_samples(void);
 int GPU_max_cube_map_size(void);
 int GPU_max_ubo_binds(void);
 int GPU_max_ubo_size(void);
+float GPU_max_line_width(void);
 int GPU_color_depth(void);
 void GPU_get_dfdy_factors(float fac[2]);
 bool GPU_mip_render_workaround(void);
diff --git a/source/blender/gpu/intern/gpu_extensions.c b/source/blender/gpu/intern/gpu_extensions.c
index 36e69f96b78..2237a6ea49c 100644
--- a/source/blender/gpu/intern/gpu_extensions.c
+++ b/source/blender/gpu/intern/gpu_extensions.c
@@ -80,6 +80,7 @@ static struct GPUGlobal {
 	GPUDeviceType device;
 	GPUOSType os;
 	GPUDriverType driver;
+	float line_width_range[2];
 	/* workaround for different calculation of dfdy factors on GPUs. Some GPUs/drivers
 	 * calculate dfdy in shader differently when drawing to an offscreen buffer. First
 	 * number is factor on screen and second is off-screen */
@@ -190,6 +191,11 @@ int GPU_max_ubo_size(void)
 	return GG.maxubosize;
 }
 
+float GPU_max_line_width(void)
+{
+	return GG.line_width_range[1];
+}
+
 void GPU_get_dfdy_factors(float fac[2])
 {
 	copy_v2_v2(fac, GG.dfdyfactors);
@@ -230,6 +236,8 @@ void gpu_extensions_init(void)
 	glGetIntegerv(GL_MAX_FRAGMENT_UNIFORM_BLOCKS, &GG.maxubobinds);
 	glGetIntegerv(GL_MAX_UNIFORM_BLOCK_SIZE, &GG.maxubosize);
 
+	glGetFloatv(GL_ALIASED_LINE_WIDTH_RANGE, GG.line_width_range);
+
 #ifndef NDEBUG
 	GLint ret;
 	glBindFramebuffer(GL_FRAMEBUFFER, 0);
diff --git a/source/blender/gpu/intern/gpu_state.c b/source/blender/gpu/intern/gpu_state.c
index 0f07b2debc3..afc8570356b 100644
--- a/source/blender/gpu/intern/gpu_state.c
+++ b/source/blender/gpu/intern/gpu_state.c
@@ -29,6 +29,7 @@
 
 #include "GPU_glew.h"
 #include "GPU_state.h"
+#include "GPU_extensions.h"
 
 static GLenum gpu_get_gl_blendfunction(GPUBlendFunction blend)
 {
@@ -118,7 +119,13 @@ void GPU_line_stipple(bool enable)
 
 void GPU_line_width(float width)
 {
-	glLineWidth(width * U.pixelsize);
+	float max_size = GPU_max_line_width();
+	float final_size = width * U.pixelsize;
+	/* Fix opengl errors on certain platform / drivers. */
+	if (max_size < final_size) {
+		final_size = max_size;
+	}
+	glLineWidth(final_size);
 }
 
 void GPU_point_size(float size)