Merge pull request #30870 from raphael10241024/fix_shadow

update algorithm about paking float to vec4 to fix shadow slipping

drivers/gles2/shaders/canvas.glsl

@@ -489,8 +489,7 @@ FRAGMENT_SHADER_CODE
 		highp float shadow_attenuation = 0.0;
 
 #ifdef USE_RGBA_SHADOWS
-
-#define SHADOW_DEPTH(m_tex, m_uv) dot(texture2D((m_tex), (m_uv)), vec4(1.0 / (256.0 * 256.0 * 256.0), 1.0 / (256.0 * 256.0), 1.0 / 256.0, 1.0))
+#define SHADOW_DEPTH(m_tex, m_uv) dot(texture2D((m_tex), (m_uv)), vec4(1.0 / (255.0 * 255.0 * 255.0), 1.0 / (255.0 * 255.0), 1.0 / 255.0, 1.0))
 
 #else
 

drivers/gles2/shaders/canvas_shadow.glsl

@@ -47,8 +47,8 @@ void main() {
 
 #ifdef USE_RGBA_SHADOWS
 
-	highp vec4 comp = fract(depth * vec4(256.0 * 256.0 * 256.0, 256.0 * 256.0, 256.0, 1.0));
-	comp -= comp.xxyz * vec4(0.0, 1.0 / 256.0, 1.0 / 256.0, 1.0 / 256.0);
+	highp vec4 comp = fract(depth * vec4(255.0 * 255.0 * 255.0, 255.0 * 255.0, 255.0, 1.0));
+	comp -= comp.xxyz * vec4(0.0, 1.0 / 255.0, 1.0 / 255.0, 1.0 / 255.0);
 	gl_FragColor = comp;
 #else
 

drivers/gles2/shaders/scene.glsl

@@ -1365,7 +1365,7 @@ LIGHT_SHADER_CODE
 
 #ifdef USE_RGBA_SHADOWS
 
-#define SHADOW_DEPTH(m_val) dot(m_val, vec4(1.0 / (256.0 * 256.0 * 256.0), 1.0 / (256.0 * 256.0), 1.0 / 256.0, 1.0))
+#define SHADOW_DEPTH(m_val) dot(m_val, vec4(1.0 / (255.0 * 255.0 * 255.0), 1.0 / (255.0 * 255.0), 1.0 / 255.0, 1.0))
 
 #else
 
@@ -2207,8 +2207,8 @@ FRAGMENT_SHADER_CODE
 #ifdef USE_RGBA_SHADOWS
 
 	highp float depth = ((position_interp.z / position_interp.w) + 1.0) * 0.5 + 0.0; // bias
-	highp vec4 comp = fract(depth * vec4(256.0 * 256.0 * 256.0, 256.0 * 256.0, 256.0, 1.0));
-	comp -= comp.xxyz * vec4(0.0, 1.0 / 256.0, 1.0 / 256.0, 1.0 / 256.0);
+	highp vec4 comp = fract(depth * vec4(255.0 * 255.0 * 255.0, 255.0 * 255.0, 255.0, 1.0));
+	comp -= comp.xxyz * vec4(0.0, 1.0 / 255.0, 1.0 / 255.0, 1.0 / 255.0);
 	gl_FragColor = comp;
 
 #endif

drivers/gles3/rasterizer_storage_gles3.cpp

@@ -8093,7 +8093,7 @@ void RasterizerStorageGLES3::initialize() {
 	glGetIntegerv(GL_MAX_TEXTURE_IMAGE_UNITS, &config.max_texture_image_units);
 	glGetIntegerv(GL_MAX_TEXTURE_SIZE, &config.max_texture_size);
 
-	config.use_rgba_2d_shadows = config.framebuffer_float_supported;
+	config.use_rgba_2d_shadows = !config.framebuffer_float_supported;
 
 	//generic quadie for copying
 

drivers/gles3/shaders/canvas.glsl

@@ -597,7 +597,7 @@ FRAGMENT_SHADER_CODE
 
 #ifdef USE_RGBA_SHADOWS
 
-#define SHADOW_DEPTH(m_tex, m_uv) dot(texture((m_tex), (m_uv)), vec4(1.0 / (256.0 * 256.0 * 256.0), 1.0 / (256.0 * 256.0), 1.0 / 256.0, 1.0))
+#define SHADOW_DEPTH(m_tex, m_uv) dot(texture((m_tex), (m_uv)), vec4(1.0 / (255.0 * 255.0 * 255.0), 1.0 / (255.0 * 255.0), 1.0 / 255.0, 1.0))
 
 #else
 

drivers/gles3/shaders/canvas_shadow.glsl

@@ -35,8 +35,8 @@ void main() {
 
 #ifdef USE_RGBA_SHADOWS
 
-	highp vec4 comp = fract(depth * vec4(256.0 * 256.0 * 256.0, 256.0 * 256.0, 256.0, 1.0));
-	comp -= comp.xxyz * vec4(0.0, 1.0 / 256.0, 1.0 / 256.0, 1.0 / 256.0);
+	highp vec4 comp = fract(depth * vec4(255.0 * 255.0 * 255.0, 255.0 * 255.0, 255.0, 1.0));
+	comp -= comp.xxyz * vec4(0.0, 1.0 / 255.0, 1.0 / 255.0, 1.0 / 255.0);
 	distance_buf = comp;
 #else