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IDProjectCategoryView StatusLast Update
0032238Open CASCADEOCCT:Visualizationpublic2023-08-01 15:09
Reporterkgv Assigned Tovpozdyayev 
PrioritynormalSeverityminor 
Status newResolutionopen 
Product Version7.5.0 
Target VersionUnscheduled 
Summary0032238: Visualization, TKOpenGl - GLSL compilation errors when using ANGLE (OpenGL ES 2.0) with disabled highp
DescriptionDisabling OpenGl_Context::hasHighp leads to the following errors:
TKOpenGl | Type: Error | ID: 0 | Severity: High | Message:
  Failed to link program object [occt_unlit0000]! Linker log:
Precisions for uniform 'occWorldViewMatrix' differ between vertex and fragment shaders

The reason is that Declarations.glsl declares matrix uniforms for both Vertex and Fragment shaders. And when highp is unsupported by hardware (very old OpenGL ES 2.0), the precision qualifiers of the same uniform become different.

In practice, the uniform is used only within vertex shader, so that Android hardware tolerated such syntax - unused uniform variables have been removed from Fragment shader before validation.
Issue happened only within Phong GLSL program, which has done matrix calculations in Framment shader until 0032042.
ANGLE library is, however, more strict about GLSL syntax and explicitly rejects such shaders.
Steps To Reproduce
pload MODELING VISUALIZATION
vdriver -load GLES
vcaps -maxVersion 2 0
# there is no such flag yet
#vcaps -highp 0
vinit View1
TagsNo tags attached.
Test case number

Relationships

related to 0032042 closedbugmaster Visualization, TKOpenGl - pre-multiply headlight flag into light source position 

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Issue History

Date Modified Username Field Change
2021-03-22 20:42 kgv New Issue
2021-03-22 20:42 kgv Assigned To => kgv
2021-03-22 20:42 kgv Relationship added related to 0032042
2021-03-22 20:43 kgv Summary Visualization, TKOpenGl - GLSL compilation errors when using ANGLE (OpenGL ES 2.0) with disable highp => Visualization, TKOpenGl - GLSL compilation errors when using ANGLE (OpenGL ES 2.0) with disabled highp
2021-03-22 20:45 kgv Steps to Reproduce Updated
2021-08-24 14:51 kgv Target Version 7.6.0 => 7.7.0
2022-08-17 11:55 kgv Target Version 7.7.0 => 7.8.0
2022-10-19 15:49 smoskvin Assigned To kgv => vpozdyayev
2023-08-01 15:09 dpasukhi Target Version 7.8.0 => Unscheduled