-Support DEPTH_TEXTURE in GLES2, fixes #25106

-Fix use of transparent framebuffers in GLES2
-Fix use of ambient color clearing in GLES2 when no environment exists.

6 files changed, 47 insertions, 32 deletions

diff --git a/drivers/gles2/rasterizer_canvas_gles2.cpp b/drivers/gles2/rasterizer_canvas_gles2.cpp
index 7d643330cc..9a49d5a7e4 100644
--- a/drivers/gles2/rasterizer_canvas_gles2.cpp
+++ b/drivers/gles2/rasterizer_canvas_gles2.cpp
@@ -115,12 +115,10 @@ void RasterizerCanvasGLES2::canvas_begin() {
 	state.using_transparent_rt = false;
 	if (storage->frame.current_rt) {
 		glBindFramebuffer(GL_FRAMEBUFFER, storage->frame.current_rt->fbo);
-		glColorMask(1, 1, 1, 1);
 		state.using_transparent_rt = storage->frame.current_rt->flags[RasterizerStorage::RENDER_TARGET_TRANSPARENT];
 	}
 
 	if (storage->frame.clear_request) {
-		glColorMask(true, true, true, true);
 		glClearColor(storage->frame.clear_request_color.r,
 				storage->frame.clear_request_color.g,
 				storage->frame.clear_request_color.b,
@@ -129,8 +127,6 @@ void RasterizerCanvasGLES2::canvas_begin() {
 		storage->frame.clear_request = false;
 	}
 
-	glColorMask(1, 1, 1, state.using_transparent_rt ? 1 : 0);
-
 	/*
 	if (storage->frame.current_rt) {
 		glBindFramebuffer(GL_FRAMEBUFFER, storage->frame.current_rt->fbo);
@@ -186,9 +182,6 @@ void RasterizerCanvasGLES2::canvas_end() {
 	state.using_texture_rect = false;
 	state.using_skeleton = false;
 	state.using_ninepatch = false;
-	if (state.using_transparent_rt) {
-		glColorMask(1, 1, 1, 1);
-	}
 	state.using_transparent_rt = false;
 }
 
@@ -1182,10 +1175,6 @@ void RasterizerCanvasGLES2::_copy_screen(const Rect2 &p_rect) {
 		ERR_FAIL();
 	}
 
-	if (state.using_transparent_rt) {
-		glColorMask(1, 1, 1, 1);
-	}
-
 	glDisable(GL_BLEND);
 
 	Vector2 wh(storage->frame.current_rt->width, storage->frame.current_rt->height);
@@ -1229,10 +1218,6 @@ void RasterizerCanvasGLES2::_copy_screen(const Rect2 &p_rect) {
 	storage->shaders.copy.set_conditional(CopyShaderGLES2::USE_COPY_SECTION, false);
 	storage->shaders.copy.set_conditional(CopyShaderGLES2::USE_NO_ALPHA, false);
 
-	if (state.using_transparent_rt) {
-		glColorMask(1, 1, 1, 0);
-	}
-
 	glBindFramebuffer(GL_FRAMEBUFFER, storage->frame.current_rt->fbo); //back to front
 	glEnable(GL_BLEND);
 }
diff --git a/drivers/gles2/rasterizer_scene_gles2.cpp b/drivers/gles2/rasterizer_scene_gles2.cpp
index 3920a5f96a..a7becdde24 100644
--- a/drivers/gles2/rasterizer_scene_gles2.cpp
+++ b/drivers/gles2/rasterizer_scene_gles2.cpp
@@ -1183,9 +1183,14 @@ bool RasterizerSceneGLES2::_setup_material(RasterizerStorageGLES2::Material *p_m
 		glBindTexture(GL_TEXTURE_2D, storage->frame.current_rt->copy_screen_effect.color);
 	}
 
+	if (p_material->shader->spatial.uses_depth_texture && storage->frame.current_rt) {
+		glActiveTexture(GL_TEXTURE0 + storage->config.max_texture_image_units - 4);
+		glBindTexture(GL_TEXTURE_2D, storage->frame.current_rt->depth);
+	}
+
 	bool shader_rebind = state.scene_shader.bind();
 
-	if (p_material->shader->spatial.no_depth_test) {
+	if (p_material->shader->spatial.no_depth_test || p_material->shader->spatial.uses_depth_texture) {
 		glDisable(GL_DEPTH_TEST);
 	} else {
 		glEnable(GL_DEPTH_TEST);
@@ -1195,10 +1200,10 @@ bool RasterizerSceneGLES2::_setup_material(RasterizerStorageGLES2::Material *p_m
 		case RasterizerStorageGLES2::Shader::Spatial::DEPTH_DRAW_ALPHA_PREPASS:
 		case RasterizerStorageGLES2::Shader::Spatial::DEPTH_DRAW_OPAQUE: {
 
-			glDepthMask(!p_alpha_pass);
+			glDepthMask(!p_alpha_pass && !p_material->shader->spatial.uses_depth_texture);
 		} break;
 		case RasterizerStorageGLES2::Shader::Spatial::DEPTH_DRAW_ALWAYS: {
-			glDepthMask(GL_TRUE);
+			glDepthMask(GL_TRUE && !p_material->shader->spatial.uses_depth_texture);
 		} break;
 		case RasterizerStorageGLES2::Shader::Spatial::DEPTH_DRAW_NEVER: {
 			glDepthMask(GL_FALSE);
@@ -2359,7 +2364,7 @@ void RasterizerSceneGLES2::_render_render_list(RenderList::Element **p_elements,
 				} else {
 					state.scene_shader.set_uniform(SceneShaderGLES2::BG_ENERGY, 1.0);
 					state.scene_shader.set_uniform(SceneShaderGLES2::AMBIENT_SKY_CONTRIBUTION, 1.0);
-					state.scene_shader.set_uniform(SceneShaderGLES2::AMBIENT_COLOR, Color(1.0, 1.0, 1.0, 1.0));
+					state.scene_shader.set_uniform(SceneShaderGLES2::AMBIENT_COLOR, state.default_ambient);
 					state.scene_shader.set_uniform(SceneShaderGLES2::AMBIENT_ENERGY, 1.0);
 				}
 
@@ -2471,7 +2476,6 @@ void RasterizerSceneGLES2::_draw_sky(RasterizerStorageGLES2::Sky *p_sky, const C
 	glDisable(GL_CULL_FACE);
 	glDisable(GL_BLEND);
 	glDepthFunc(GL_LEQUAL);
-	glColorMask(1, 1, 1, 1);
 
 	// Camera
 	CameraMatrix camera;
@@ -2673,7 +2677,7 @@ void RasterizerSceneGLES2::render_scene(const Transform &p_cam_transform, const
 
 	// clear color
 
-	Color clear_color(0, 0, 0, 0);
+	Color clear_color(0, 0, 0, 1);
 
 	if (storage->frame.current_rt && storage->frame.current_rt->flags[RasterizerStorage::RENDER_TARGET_TRANSPARENT]) {
 		clear_color = Color(0, 0, 0, 0);
@@ -2694,6 +2698,8 @@ void RasterizerSceneGLES2::render_scene(const Transform &p_cam_transform, const
 		glClearColor(clear_color.r, clear_color.g, clear_color.b, clear_color.a);
 	}
 
+	state.default_ambient = Color(clear_color.r, clear_color.g, clear_color.b, 1.0);
+
 	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 
 	glVertexAttrib4f(VS::ARRAY_COLOR, 1, 1, 1, 1);
diff --git a/drivers/gles2/rasterizer_scene_gles2.h b/drivers/gles2/rasterizer_scene_gles2.h
index 0d917f4da2..aab9ae0fdc 100644
--- a/drivers/gles2/rasterizer_scene_gles2.h
+++ b/drivers/gles2/rasterizer_scene_gles2.h
@@ -103,6 +103,7 @@ public:
 		GLuint sky_verts;
 
 		GLuint immediate_buffer;
+		Color default_ambient;
 
 		// ResolveShaderGLES3 resolve_shader;
 		// ScreenSpaceReflectionShaderGLES3 ssr_shader;
diff --git a/drivers/gles2/rasterizer_storage_gles2.cpp b/drivers/gles2/rasterizer_storage_gles2.cpp
index 0227cd2b34..aca1e2d7c2 100644
--- a/drivers/gles2/rasterizer_storage_gles2.cpp
+++ b/drivers/gles2/rasterizer_storage_gles2.cpp
@@ -1230,6 +1230,10 @@ void RasterizerStorageGLES2::_update_shader(Shader *p_shader) const {
 
 			actions = &shaders.actions_scene;
 			actions->uniforms = &p_shader->uniforms;
+
+			if (p_shader->spatial.uses_screen_texture && p_shader->spatial.uses_depth_texture) {
+				WARN_PRINT("Using both SCREEN_TEXTURE and DEPTH_TEXTURE is not supported in GLES2");
+			}
 		} break;
 
 		default: {
@@ -4200,7 +4204,12 @@ void RasterizerStorageGLES2::_render_target_allocate(RenderTarget *rt) {
 
 	glGenTextures(1, &rt->color);
 	glBindTexture(GL_TEXTURE_2D, rt->color);
-	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, rt->width, rt->height, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);
+
+	if (rt->flags[RasterizerStorage::RENDER_TARGET_TRANSPARENT]) {
+		glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, rt->width, rt->height, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);
+	} else {
+		glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, rt->width, rt->height, 0, GL_RGB, GL_UNSIGNED_BYTE, NULL);
+	}
 
 	if (texture->flags & VS::TEXTURE_FLAG_FILTER) {
 
@@ -4218,20 +4227,26 @@ void RasterizerStorageGLES2::_render_target_allocate(RenderTarget *rt) {
 
 	// depth
 
-	glGenRenderbuffers(1, &rt->depth);
-	glBindRenderbuffer(GL_RENDERBUFFER, rt->depth);
+	glGenTextures(1, &rt->depth);
+	glBindTexture(GL_TEXTURE_2D, rt->depth);
+
 #ifdef JAVASCRIPT_ENABLED
-	glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT16, rt->width, rt->height);
+	glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT, rt->width, rt->height, 0, GL_DEPTH_COMPONENT, GL_UNSIGNED_INT, NULL);
 #else
-	glRenderbufferStorage(GL_RENDERBUFFER, _DEPTH_COMPONENT24_OES, rt->width, rt->height);
+	glTexImage2D(GL_TEXTURE_2D, 0, _DEPTH_COMPONENT24_OES, rt->width, rt->height, 0, GL_DEPTH_COMPONENT, GL_UNSIGNED_INT, NULL);
 #endif
-	glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, rt->depth);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+
+	glFramebufferTexture2D(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_TEXTURE_2D, rt->depth, 0);
 
 	GLenum status = glCheckFramebufferStatus(GL_FRAMEBUFFER);
 
 	if (status != GL_FRAMEBUFFER_COMPLETE) {
 
-		glDeleteRenderbuffers(1, &rt->fbo);
+		glDeleteFramebuffers(1, &rt->fbo);
 		glDeleteTextures(1, &rt->depth);
 		glDeleteTextures(1, &rt->color);
 		rt->fbo = 0;
@@ -4270,7 +4285,12 @@ void RasterizerStorageGLES2::_render_target_allocate(RenderTarget *rt) {
 		glGenTextures(1, &rt->copy_screen_effect.color);
 		glBindTexture(GL_TEXTURE_2D, rt->copy_screen_effect.color);
 
-		glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, w, h, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);
+		if (rt->flags[RasterizerStorage::RENDER_TARGET_TRANSPARENT]) {
+			glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, rt->width, rt->height, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);
+		} else {
+			glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, rt->width, rt->height, 0, GL_RGB, GL_UNSIGNED_BYTE, NULL);
+		}
+
 		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
 		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
 		glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
@@ -4302,7 +4322,7 @@ void RasterizerStorageGLES2::_render_target_clear(RenderTarget *rt) {
 	}
 
 	if (rt->depth) {
-		glDeleteRenderbuffers(1, &rt->depth);
+		glDeleteTextures(1, &rt->depth);
 		rt->depth = 0;
 	}
 
@@ -4313,7 +4333,6 @@ void RasterizerStorageGLES2::_render_target_clear(RenderTarget *rt) {
 	tex->height = 0;
 	tex->active = false;
 
-	// TODO hardcoded texscreen copy effect
 	if (rt->copy_screen_effect.color) {
 		glDeleteFramebuffers(1, &rt->copy_screen_effect.fbo);
 		rt->copy_screen_effect.fbo = 0;
diff --git a/drivers/gles2/shader_compiler_gles2.cpp b/drivers/gles2/shader_compiler_gles2.cpp
index 15897fe587..fdd905458b 100644
--- a/drivers/gles2/shader_compiler_gles2.cpp
+++ b/drivers/gles2/shader_compiler_gles2.cpp
@@ -859,7 +859,7 @@ ShaderCompilerGLES2::ShaderCompilerGLES2() {
 	actions[VS::SHADER_SPATIAL].renames["INSTANCE_CUSTOM"] = "instance_custom";
 	actions[VS::SHADER_SPATIAL].renames["SCREEN_UV"] = "screen_uv";
 	actions[VS::SHADER_SPATIAL].renames["SCREEN_TEXTURE"] = "screen_texture";
-	actions[VS::SHADER_SPATIAL].renames["DEPTH_TEXTURE"] = "depth_buffer";
+	actions[VS::SHADER_SPATIAL].renames["DEPTH_TEXTURE"] = "depth_texture";
 	// Defined in GLES3, but not available in GLES2
 	//actions[VS::SHADER_SPATIAL].renames["DEPTH"] = "gl_FragDepth";
 	actions[VS::SHADER_SPATIAL].renames["ALPHA_SCISSOR"] = "alpha_scissor";
@@ -895,6 +895,7 @@ ShaderCompilerGLES2::ShaderCompilerGLES2() {
 	actions[VS::SHADER_SPATIAL].usage_defines["SSS_STRENGTH"] = "#define ENABLE_SSS\n";
 	actions[VS::SHADER_SPATIAL].usage_defines["TRANSMISSION"] = "#define TRANSMISSION_USED\n";
 	actions[VS::SHADER_SPATIAL].usage_defines["SCREEN_TEXTURE"] = "#define SCREEN_TEXTURE_USED\n";
+	actions[VS::SHADER_SPATIAL].usage_defines["DEPTH_TEXTURE"] = "#define DEPTH_TEXTURE_USED\n";
 	actions[VS::SHADER_SPATIAL].usage_defines["SCREEN_UV"] = "#define SCREEN_UV_USED\n";
 
 	actions[VS::SHADER_SPATIAL].usage_defines["DIFFUSE_LIGHT"] = "#define USE_LIGHT_SHADER_CODE\n";
diff --git a/drivers/gles2/shaders/scene.glsl b/drivers/gles2/shaders/scene.glsl
index 327fb65e8e..6f86152598 100644
--- a/drivers/gles2/shaders/scene.glsl
+++ b/drivers/gles2/shaders/scene.glsl
@@ -724,6 +724,9 @@ uniform vec2 screen_pixel_size;
 #if defined(SCREEN_TEXTURE_USED)
 uniform highp sampler2D screen_texture; //texunit:-4
 #endif
+#if defined(DEPTH_TEXTURE_USED)
+uniform highp sampler2D depth_texture; //texunit:-4
+#endif
 
 #ifdef USE_REFLECTION_PROBE1