From 90e837ffd1ff5c9add1074d69de23e58a3a4810e Mon Sep 17 00:00:00 2001 From: Alyssa Rosenzweig Date: Wed, 11 Nov 2020 09:26:03 -0500 Subject: [PATCH 1/3] terrain: Fix precision bug in light rendering Resulting in overly bright rendering when mediump is implemented as fp16. Signed-off-by: Alyssa Rosenzweig --- data/shaders/terrain.frag | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/data/shaders/terrain.frag b/data/shaders/terrain.frag index 84d085c..58f17ea 100644 --- a/data/shaders/terrain.frag +++ b/data/shaders/terrain.frag @@ -67,7 +67,12 @@ void main() { vec3 pointSpecular = vec3( 0.0 ); for ( int i = 0; i < MAX_POINT_LIGHTS; i ++ ) { vec4 lPosition = viewMatrix * vec4( pointLightPosition[ i ], 1.0 ); +#ifdef GL_FRAGMENT_PRECISION_HIGH + // should be highp for correct behaviour if mediump is implemented as fp16 + highp vec3 lVector = lPosition.xyz + vViewPosition.xyz; +#else vec3 lVector = lPosition.xyz + vViewPosition.xyz; +#endif float lDistance = 1.0; if ( pointLightDistance[ i ] > 0.0 ) lDistance = 1.0 - min( ( length( lVector ) / pointLightDistance[ i ] ), 1.0 ); From 1edd76fda77edabd49d713912aee49b8360c86c3 Mon Sep 17 00:00:00 2001 From: Alyssa Rosenzweig Date: Wed, 11 Nov 2020 09:49:52 -0500 Subject: [PATCH 2/3] terrain: Fix precision handling in noise shader Another overflow resulting in infinity in mediump. Note this bug is masked if the driver clamps infinity to MAX_FLOAT, but it's still our bug. Signed-off-by: Alyssa Rosenzweig --- data/shaders/terrain-noise.frag | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/data/shaders/terrain-noise.frag b/data/shaders/terrain-noise.frag index 7fea5c0..9535e58 100644 --- a/data/shaders/terrain-noise.frag +++ b/data/shaders/terrain-noise.frag @@ -17,7 +17,13 @@ uniform float time; uniform MEDIUMP vec2 uvScale; varying vec2 vUv; +#ifdef GL_FRAGMENT_PRECISION_HIGH +// x should be passed as highp since the intermediate multiplications can +// overflow with mediump +vec4 permute(highp vec4 x) +#else vec4 permute(vec4 x) +#endif { return mod(((x * 34.0) + 1.0) * x, 289.0); } From e866cc633ffc450e5358b2742f32ca360e4f3f12 Mon Sep 17 00:00:00 2001 From: Alyssa Rosenzweig Date: Wed, 11 Nov 2020 09:35:21 -0500 Subject: [PATCH 3/3] loop,function,conditionals: Fix mediump overflow The multiplication can produce infinity. Signed-off-by: Alyssa Rosenzweig --- data/shaders/conditionals.frag | 9 ++++++++- data/shaders/function.frag | 9 ++++++++- data/shaders/loop.frag | 9 ++++++++- 3 files changed, 24 insertions(+), 3 deletions(-) diff --git a/data/shaders/conditionals.frag b/data/shaders/conditionals.frag index 3bd2507..e902263 100644 --- a/data/shaders/conditionals.frag +++ b/data/shaders/conditionals.frag @@ -2,7 +2,14 @@ varying vec4 dummy; void main(void) { - float d = fract(gl_FragCoord.x * gl_FragCoord.y * 0.0001); +#ifdef GL_FRAGMENT_PRECISION_HIGH + // should be declared highp since the multiplication can overflow in + // mediump, particularly if mediump is implemented as fp16 + highp vec2 FragCoord = gl_FragCoord.xy; +#else + vec2 FragCoord = gl_FragCoord.xy; +#endif + float d = fract(FragCoord.x * FragCoord.y * 0.0001); $MAIN$ diff --git a/data/shaders/function.frag b/data/shaders/function.frag index 3e3c74f..9d0230e 100644 --- a/data/shaders/function.frag +++ b/data/shaders/function.frag @@ -8,7 +8,14 @@ $PROCESS$ void main(void) { - float d = fract(gl_FragCoord.x * gl_FragCoord.y * 0.0001); +#ifdef GL_FRAGMENT_PRECISION_HIGH + // should be declared highp since the multiplication can overflow in + // mediump, particularly if mediump is implemented as fp16 + highp vec2 FragCoord = gl_FragCoord.xy; +#else + vec2 FragCoord = gl_FragCoord.xy; +#endif + float d = fract(FragCoord.x * FragCoord.y * 0.0001); $MAIN$ diff --git a/data/shaders/loop.frag b/data/shaders/loop.frag index 31ae23e..9a6afd2 100644 --- a/data/shaders/loop.frag +++ b/data/shaders/loop.frag @@ -3,7 +3,14 @@ uniform int FragmentLoops; void main(void) { - float d = fract(gl_FragCoord.x * gl_FragCoord.y * 0.0001); +#ifdef GL_FRAGMENT_PRECISION_HIGH + // should be declared highp since the multiplication can overflow in + // mediump, particularly if mediump is implemented as fp16 + highp vec2 FragCoord = gl_FragCoord.xy; +#else + vec2 FragCoord = gl_FragCoord.xy; +#endif + float d = fract(FragCoord.x * FragCoord.y * 0.0001); $MAIN$