From 57416bfbce17905e71d143478a796dc6b27ba4f7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?R=C3=A9mi=20Verschelde?= <rverschelde@gmail.com>
Date: Fri, 21 Dec 2018 15:14:55 +0100
Subject: [PATCH] GLES2: Define 'lowp' for OpenGL 2.1

Precision qualifiers are only used on OpenGL ES 2.0 and 3.0,
and while OpenGL 3.3 defines them for compatibility (but without
practical effect), they're missing from OpenGL 2.1, so we define
them to prevent compilation errors.

Fixes #24521.
---
 drivers/gles2/shaders/canvas.glsl         | 8 ++------
 drivers/gles2/shaders/canvas_shadow.glsl  | 3 ++-
 drivers/gles2/shaders/copy.glsl           | 2 ++
 drivers/gles2/shaders/cube_to_dp.glsl     | 2 ++
 drivers/gles2/shaders/cubemap_filter.glsl | 2 ++
 drivers/gles2/shaders/lens_distorted.glsl | 2 ++
 drivers/gles2/shaders/scene.glsl          | 2 ++
 7 files changed, 14 insertions(+), 7 deletions(-)

diff --git a/drivers/gles2/shaders/canvas.glsl b/drivers/gles2/shaders/canvas.glsl
index 01a90d07254..614124e6d93 100644
--- a/drivers/gles2/shaders/canvas.glsl
+++ b/drivers/gles2/shaders/canvas.glsl
@@ -2,6 +2,7 @@
 [vertex]
 
 #ifdef USE_GLES_OVER_GL
+#define lowp
 #define mediump
 #define highp
 #else
@@ -31,8 +32,6 @@ uniform vec4 src_rect;
 
 uniform highp float time;
 
-
-
 #ifdef USE_LIGHTING
 
 // light matrices
@@ -62,7 +61,6 @@ const bool at_light_pass = true;
 const bool at_light_pass = false;
 #endif
 
-
 /* clang-format off */
 
 VERTEX_SHADER_GLOBALS
@@ -80,7 +78,6 @@ vec2 select(vec2 a, vec2 b, bvec2 c) {
 
 void main() {
 
-
 	vec4 color = color_attrib;
 
 #ifdef USE_INSTANCING
@@ -159,13 +156,13 @@ VERTEX_SHADER_CODE
 #endif
 
 #endif
-
 }
 
 /* clang-format off */
 [fragment]
 
 #ifdef USE_GLES_OVER_GL
+#define lowp
 #define mediump
 #define highp
 #else
@@ -231,7 +228,6 @@ const bool at_light_pass = false;
 
 uniform bool use_default_normal;
 
-
 /* clang-format off */
 
 FRAGMENT_SHADER_GLOBALS
diff --git a/drivers/gles2/shaders/canvas_shadow.glsl b/drivers/gles2/shaders/canvas_shadow.glsl
index 51af004e392..d39212826e8 100644
--- a/drivers/gles2/shaders/canvas_shadow.glsl
+++ b/drivers/gles2/shaders/canvas_shadow.glsl
@@ -2,6 +2,7 @@
 [vertex]
 
 #ifdef USE_GLES_OVER_GL
+#define lowp
 #define mediump
 #define highp
 #else
@@ -29,6 +30,7 @@ void main() {
 [fragment]
 
 #ifdef USE_GLES_OVER_GL
+#define lowp
 #define mediump
 #define highp
 #else
@@ -39,7 +41,6 @@ precision mediump int;
 varying highp vec4 position_interp;
 /* clang-format on */
 
-
 void main() {
 
 	highp float depth = ((position_interp.z / position_interp.w) + 1.0) * 0.5 + 0.0; // bias
diff --git a/drivers/gles2/shaders/copy.glsl b/drivers/gles2/shaders/copy.glsl
index 97a24212a54..f3c2a7eec44 100644
--- a/drivers/gles2/shaders/copy.glsl
+++ b/drivers/gles2/shaders/copy.glsl
@@ -2,6 +2,7 @@
 [vertex]
 
 #ifdef USE_GLES_OVER_GL
+#define lowp
 #define mediump
 #define highp
 #else
@@ -56,6 +57,7 @@ void main() {
 #define M_PI 3.14159265359
 
 #ifdef USE_GLES_OVER_GL
+#define lowp
 #define mediump
 #define highp
 #else
diff --git a/drivers/gles2/shaders/cube_to_dp.glsl b/drivers/gles2/shaders/cube_to_dp.glsl
index 3d24c363367..cb4b3f6dec0 100644
--- a/drivers/gles2/shaders/cube_to_dp.glsl
+++ b/drivers/gles2/shaders/cube_to_dp.glsl
@@ -2,6 +2,7 @@
 [vertex]
 
 #ifdef USE_GLES_OVER_GL
+#define lowp
 #define mediump
 #define highp
 #else
@@ -25,6 +26,7 @@ void main() {
 [fragment]
 
 #ifdef USE_GLES_OVER_GL
+#define lowp
 #define mediump
 #define highp
 #else
diff --git a/drivers/gles2/shaders/cubemap_filter.glsl b/drivers/gles2/shaders/cubemap_filter.glsl
index b1553c7cd5a..06274a76984 100644
--- a/drivers/gles2/shaders/cubemap_filter.glsl
+++ b/drivers/gles2/shaders/cubemap_filter.glsl
@@ -2,6 +2,7 @@
 [vertex]
 
 #ifdef USE_GLES_OVER_GL
+#define lowp
 #define mediump
 #define highp
 #else
@@ -32,6 +33,7 @@ void main() {
 #endif
 
 #ifdef USE_GLES_OVER_GL
+#define lowp
 #define mediump
 #define highp
 #else
diff --git a/drivers/gles2/shaders/lens_distorted.glsl b/drivers/gles2/shaders/lens_distorted.glsl
index efa35adf7d5..81898a75a52 100644
--- a/drivers/gles2/shaders/lens_distorted.glsl
+++ b/drivers/gles2/shaders/lens_distorted.glsl
@@ -2,6 +2,7 @@
 [vertex]
 
 #ifdef USE_GLES_OVER_GL
+#define lowp
 #define mediump
 #define highp
 #else
@@ -29,6 +30,7 @@ void main() {
 [fragment]
 
 #ifdef USE_GLES_OVER_GL
+#define lowp
 #define mediump
 #define highp
 #else
diff --git a/drivers/gles2/shaders/scene.glsl b/drivers/gles2/shaders/scene.glsl
index 32721c892b0..4f334d2be28 100644
--- a/drivers/gles2/shaders/scene.glsl
+++ b/drivers/gles2/shaders/scene.glsl
@@ -2,6 +2,7 @@
 [vertex]
 
 #ifdef USE_GLES_OVER_GL
+#define lowp
 #define mediump
 #define highp
 #else
@@ -653,6 +654,7 @@ VERTEX_SHADER_CODE
 #endif
 
 #ifdef USE_GLES_OVER_GL
+#define lowp
 #define mediump
 #define highp
 #else