Moving lens distortion shader into drivers and adding GLES2 support

6 files changed, 123 insertions, 0 deletions

diff --git a/drivers/gles3/rasterizer_canvas_gles3.cpp b/drivers/gles3/rasterizer_canvas_gles3.cpp
index 856c83e297..a9b46baf53 100644
--- a/drivers/gles3/rasterizer_canvas_gles3.cpp
+++ b/drivers/gles3/rasterizer_canvas_gles3.cpp
@@ -1869,6 +1869,39 @@ void RasterizerCanvasGLES3::draw_generic_textured_rect(const Rect2 &p_rect, cons
 	glDrawArrays(GL_TRIANGLE_FAN, 0, 4);
 }
 
+void RasterizerCanvasGLES3::draw_lens_distortion_rect(const Rect2 &p_rect, float p_k1, float p_k2, const Vector2 &p_eye_center, float p_oversample) {
+	Vector2 half_size;
+	if (storage->frame.current_rt) {
+		half_size = Vector2(storage->frame.current_rt->width, storage->frame.current_rt->height);
+	} else {
+		half_size = OS::get_singleton()->get_window_size();
+	}
+	half_size *= 0.5;
+	Vector2 offset((p_rect.position.x - half_size.x) / half_size.x, (p_rect.position.y - half_size.y) / half_size.y);
+	Vector2 scale(p_rect.size.x / half_size.x, p_rect.size.y / half_size.y);
+
+	float aspect_ratio = p_rect.size.x / p_rect.size.y;
+
+	// setup our lens shader
+	state.lens_shader.bind();
+	state.lens_shader.set_uniform(LensDistortedShaderGLES3::OFFSET, offset);
+	state.lens_shader.set_uniform(LensDistortedShaderGLES3::SCALE, scale);
+	state.lens_shader.set_uniform(LensDistortedShaderGLES3::K1, p_k1);
+	state.lens_shader.set_uniform(LensDistortedShaderGLES3::K2, p_k2);
+	state.lens_shader.set_uniform(LensDistortedShaderGLES3::EYE_CENTER, p_eye_center);
+	state.lens_shader.set_uniform(LensDistortedShaderGLES3::UPSCALE, p_oversample);
+	state.lens_shader.set_uniform(LensDistortedShaderGLES3::ASPECT_RATIO, aspect_ratio);
+
+	glBindBufferBase(GL_UNIFORM_BUFFER, 0, state.canvas_item_ubo);
+	glBindVertexArray(data.canvas_quad_array);
+
+	// and draw
+	glDrawArrays(GL_TRIANGLE_FAN, 0, 4);
+
+	glBindVertexArray(0);
+	glBindBufferBase(GL_UNIFORM_BUFFER, 0, 0);
+}
+
 void RasterizerCanvasGLES3::draw_window_margins(int *black_margin, RID *black_image) {
 
 	Vector2 window_size = OS::get_singleton()->get_window_size();
@@ -2058,6 +2091,7 @@ void RasterizerCanvasGLES3::initialize() {
 	state.canvas_shader.init();
 	state.canvas_shader.set_base_material_tex_index(2);
 	state.canvas_shadow_shader.init();
+	state.lens_shader.init();
 
 	state.canvas_shader.set_conditional(CanvasShaderGLES3::USE_RGBA_SHADOWS, storage->config.use_rgba_2d_shadows);
 	state.canvas_shadow_shader.set_conditional(CanvasShadowShaderGLES3::USE_RGBA_SHADOWS, storage->config.use_rgba_2d_shadows);
diff --git a/drivers/gles3/rasterizer_canvas_gles3.h b/drivers/gles3/rasterizer_canvas_gles3.h
index bc4ea80328..3f306003b4 100644
--- a/drivers/gles3/rasterizer_canvas_gles3.h
+++ b/drivers/gles3/rasterizer_canvas_gles3.h
@@ -35,6 +35,7 @@
 #include "servers/visual/rasterizer.h"
 
 #include "shaders/canvas_shadow.glsl.gen.h"
+#include "shaders/lens_distorted.glsl.gen.h"
 
 class RasterizerSceneGLES3;
 
@@ -72,6 +73,7 @@ public:
 		bool canvas_texscreen_used;
 		CanvasShaderGLES3 canvas_shader;
 		CanvasShadowShaderGLES3 canvas_shadow_shader;
+		LensDistortedShaderGLES3 lens_shader;
 
 		bool using_texture_rect;
 		bool using_ninepatch;
@@ -141,6 +143,7 @@ public:
 	virtual void reset_canvas();
 
 	void draw_generic_textured_rect(const Rect2 &p_rect, const Rect2 &p_src);
+	void draw_lens_distortion_rect(const Rect2 &p_rect, float p_k1, float p_k2, const Vector2 &p_eye_center, float p_oversample);
 
 	void initialize();
 	void finalize();
diff --git a/drivers/gles3/rasterizer_gles3.cpp b/drivers/gles3/rasterizer_gles3.cpp
index 6f13df621f..a97cd32faa 100644
--- a/drivers/gles3/rasterizer_gles3.cpp
+++ b/drivers/gles3/rasterizer_gles3.cpp
@@ -359,6 +359,26 @@ void RasterizerGLES3::blit_render_target_to_screen(RID p_render_target, const Re
 #endif
 }
 
+void RasterizerGLES3::output_lens_distorted_to_screen(RID p_render_target, const Rect2 &p_screen_rect, float p_k1, float p_k2, const Vector2 &p_eye_center, float p_oversample) {
+	ERR_FAIL_COND(storage->frame.current_rt);
+
+	RasterizerStorageGLES3::RenderTarget *rt = storage->render_target_owner.getornull(p_render_target);
+	ERR_FAIL_COND(!rt);
+
+	glDisable(GL_BLEND);
+
+	// render to our framebuffer
+	glBindFramebuffer(GL_FRAMEBUFFER, RasterizerStorageGLES3::system_fbo);
+
+	// output our texture
+	glActiveTexture(GL_TEXTURE0);
+	glBindTexture(GL_TEXTURE_2D, rt->color);
+
+	canvas->draw_lens_distortion_rect(p_screen_rect, p_k1, p_k2, p_eye_center, p_oversample);
+
+	glBindTexture(GL_TEXTURE_2D, 0);
+}
+
 void RasterizerGLES3::end_frame(bool p_swap_buffers) {
 
 	if (OS::get_singleton()->is_layered_allowed()) {
diff --git a/drivers/gles3/rasterizer_gles3.h b/drivers/gles3/rasterizer_gles3.h
index 543011aff3..477e0dfd48 100644
--- a/drivers/gles3/rasterizer_gles3.h
+++ b/drivers/gles3/rasterizer_gles3.h
@@ -59,6 +59,7 @@ public:
 	virtual void restore_render_target();
 	virtual void clear_render_target(const Color &p_color);
 	virtual void blit_render_target_to_screen(RID p_render_target, const Rect2 &p_screen_rect, int p_screen = 0);
+	virtual void output_lens_distorted_to_screen(RID p_render_target, const Rect2 &p_screen_rect, float p_k1, float p_k2, const Vector2 &p_eye_center, float p_oversample);
 	virtual void end_frame(bool p_swap_buffers);
 	virtual void finalize();
 
diff --git a/drivers/gles3/shaders/SCsub b/drivers/gles3/shaders/SCsub
index f1811fa7b5..27fd1514e7 100644
--- a/drivers/gles3/shaders/SCsub
+++ b/drivers/gles3/shaders/SCsub
@@ -20,3 +20,4 @@ if 'GLES3_GLSL' in env['BUILDERS']:
     env.GLES3_GLSL('exposure.glsl');
     env.GLES3_GLSL('tonemap.glsl');
     env.GLES3_GLSL('particles.glsl');
+    env.GLES3_GLSL('lens_distorted.glsl');
diff --git a/drivers/gles3/shaders/lens_distorted.glsl b/drivers/gles3/shaders/lens_distorted.glsl
new file mode 100644
index 0000000000..7b9d0b347f
--- /dev/null
+++ b/drivers/gles3/shaders/lens_distorted.glsl
@@ -0,0 +1,64 @@
+/* clang-format off */
+[vertex]
+
+layout(location = 0) in highp vec4 vertex_attrib;
+/* clang-format on */
+
+uniform vec2 offset;
+uniform vec2 scale;
+
+out vec2 uv_interp;
+
+void main() {
+
+	uv_interp = vertex_attrib.xy * 2.0 - 1.0;
+
+	vec2 v = vertex_attrib.xy * scale + offset;
+	gl_Position = vec4(v, 0.0, 1.0);
+}
+
+/* clang-format off */
+[fragment]
+
+uniform sampler2D source; //texunit:0
+/* clang-format on */
+
+uniform vec2 eye_center;
+uniform float k1;
+uniform float k2;
+uniform float upscale;
+uniform float aspect_ratio;
+
+in vec2 uv_interp;
+
+layout(location = 0) out vec4 frag_color;
+
+void main() {
+	vec2 coords = uv_interp;
+	vec2 offset = coords - eye_center;
+
+	// take aspect ratio into account
+	offset.y /= aspect_ratio;
+
+	// distort
+	vec2 offset_sq = offset * offset;
+	float radius_sq = offset_sq.x + offset_sq.y;
+	float radius_s4 = radius_sq * radius_sq;
+	float distortion_scale = 1.0 + (k1 * radius_sq) + (k2 * radius_s4);
+	offset *= distortion_scale;
+
+	// reapply aspect ratio
+	offset.y *= aspect_ratio;
+
+	// add our eye center back in
+	coords = offset + eye_center;
+	coords /= upscale;
+
+	// and check our color
+	if (coords.x < -1.0 || coords.y < -1.0 || coords.x > 1.0 || coords.y > 1.0) {
+		frag_color = vec4(0.0, 0.0, 0.0, 1.0);
+	} else {
+		coords = (coords + vec2(1.0)) / vec2(2.0);
+		frag_color = textureLod(source, coords, 0.0);
+	}
+}