Ensure WebGL uses highp by default, and fix some wrong mediump usages. Fixes #22962.

drivers/gles2/shader_gles2.cpp

@@ -242,6 +242,11 @@ ShaderGLES2::Version *ShaderGLES2::get_current_version() {
 	strings.push_back("#define USE_GLES_OVER_GL\n");
 #else
 	strings.push_back("#version 100\n");
+//angle does not like
+#ifdef JAVASCRIPT_ENABLED
+	strings.push_back("#define USE_HIGHP_PRECISION\n");
+#endif
+
 #endif
 
 	int define_line_ofs = 1;

drivers/gles2/shaders/canvas.glsl

@@ -6,8 +6,8 @@
 #define mediump
 #define highp
 #else
-precision mediump float;
-precision mediump int;
+precision highp float;
+precision highp int;
 #endif
 
 uniform highp mat4 projection_matrix;
@@ -243,9 +243,14 @@ VERTEX_SHADER_CODE
 #define mediump
 #define highp
 #else
+#if defined(USE_HIGHP_PRECISION)
+precision highp float;
+precision highp int;
+#else
 precision mediump float;
 precision mediump int;
 #endif
+#endif
 
 uniform sampler2D color_texture; // texunit:-1
 /* clang-format on */

drivers/gles2/shaders/copy.glsl

@@ -6,8 +6,8 @@
 #define mediump
 #define highp
 #else
-precision mediump float;
-precision mediump int;
+precision highp float;
+precision highp int;
 #endif
 
 attribute highp vec4 vertex_attrib; // attrib:0
@@ -61,9 +61,14 @@ void main() {
 #define mediump
 #define highp
 #else
+#if defined(USE_HIGHP_PRECISION)
+precision highp float;
+precision highp int;
+#else
 precision mediump float;
 precision mediump int;
 #endif
+#endif
 
 #if defined(USE_CUBEMAP) || defined(USE_PANORAMA)
 varying vec3 cube_interp;

drivers/gles2/shaders/cubemap_filter.glsl

@@ -6,8 +6,8 @@
 #define mediump
 #define highp
 #else
-precision mediump float;
-precision mediump int;
+precision highp float;
+precision highp int;
 #endif
 
 attribute highp vec2 vertex; // attrib:0
@@ -51,10 +51,16 @@ void main() {
 #define mediump
 #define highp
 #else
+#if defined(USE_HIGHP_PRECISION)
+precision highp float;
+precision highp int;
+#else
 precision mediump float;
 precision mediump int;
 #endif
 
+#endif
+
 #ifdef USE_SOURCE_PANORAMA
 uniform sampler2D source_panorama; //texunit:0
 #else

drivers/gles2/shaders/scene.glsl

@@ -683,8 +683,13 @@ VERTEX_SHADER_CODE
 #define mediump
 #define highp
 #else
-precision mediump float;
+#if defined(USE_HIGHP_PRECISION)
+precision highp float;
 precision highp int;
+#else
+precision mediump float;
+precision mediump int;
+#endif
 #endif
 
 #include "stdlib.glsl"