1 files changed, 671 insertions, 0 deletions

diff --git a/sway/desktop/fx_renderer/fx_renderer.c b/sway/desktop/fx_renderer/fx_renderer.c
new file mode 100644
index 00000000..36c5bb61
--- /dev/null
+++ b/sway/desktop/fx_renderer/fx_renderer.c
@@ -0,0 +1,671 @@
+/*
+	The original wlr_renderer was heavily referenced in making this project
+	https://gitlab.freedesktop.org/wlroots/wlroots/-/tree/master/render/gles2
+*/
+
+#include <assert.h>
+#include <GLES2/gl2.h>
+#include <stdlib.h>
+#include <wlr/backend.h>
+#include <wlr/render/egl.h>
+#include <wlr/render/gles2.h>
+#include <wlr/types/wlr_matrix.h>
+#include <wlr/util/box.h>
+
+#include "log.h"
+#include "sway/desktop/fx_renderer/fx_renderer.h"
+#include "sway/desktop/fx_renderer/matrix.h"
+#include "sway/output.h"
+#include "sway/server.h"
+
+// shaders
+#include "box_shadow_frag_src.h"
+#include "common_vert_src.h"
+#include "corner_frag_src.h"
+#include "quad_frag_src.h"
+#include "quad_round_frag_src.h"
+#include "tex_frag_src.h"
+
+static const GLfloat verts[] = {
+	1, 0, // top right
+	0, 0, // top left
+	1, 1, // bottom right
+	0, 1, // bottom left
+};
+
+static GLuint compile_shader(GLuint type, const GLchar *src) {
+	GLuint shader = glCreateShader(type);
+	glShaderSource(shader, 1, &src, NULL);
+	glCompileShader(shader);
+
+	GLint ok;
+	glGetShaderiv(shader, GL_COMPILE_STATUS, &ok);
+	if (ok == GL_FALSE) {
+		sway_log(SWAY_ERROR, "Failed to compile shader");
+		glDeleteShader(shader);
+		shader = 0;
+	}
+
+	return shader;
+}
+
+static GLuint link_program(const GLchar *frag_src) {
+	const GLchar *vert_src = common_vert_src;
+	GLuint vert = compile_shader(GL_VERTEX_SHADER, vert_src);
+	if (!vert) {
+		goto error;
+	}
+
+	GLuint frag = compile_shader(GL_FRAGMENT_SHADER, frag_src);
+	if (!frag) {
+		glDeleteShader(vert);
+		goto error;
+	}
+
+	GLuint prog = glCreateProgram();
+	glAttachShader(prog, vert);
+	glAttachShader(prog, frag);
+	glLinkProgram(prog);
+
+	glDetachShader(prog, vert);
+	glDetachShader(prog, frag);
+	glDeleteShader(vert);
+	glDeleteShader(frag);
+
+	GLint ok;
+	glGetProgramiv(prog, GL_LINK_STATUS, &ok);
+	if (ok == GL_FALSE) {
+		sway_log(SWAY_ERROR, "Failed to link shader");
+		glDeleteProgram(prog);
+		goto error;
+	}
+
+	return prog;
+
+error:
+	return 0;
+}
+
+static bool link_tex_program(struct fx_renderer *renderer,
+		struct gles2_tex_shader *shader, enum fx_tex_shader_source source) {
+	GLchar frag_src[2048];
+	snprintf(frag_src, sizeof(frag_src),
+		"#define SOURCE %d\n%s", source, tex_frag_src);
+
+	GLuint prog;
+	shader->program = prog = link_program(frag_src);
+	if (!shader->program) {
+		return false;
+	}
+
+	shader->proj = glGetUniformLocation(prog, "proj");
+	shader->tex = glGetUniformLocation(prog, "tex");
+	shader->alpha = glGetUniformLocation(prog, "alpha");
+	shader->dim = glGetUniformLocation(prog, "dim");
+	shader->dim_color = glGetUniformLocation(prog, "dim_color");
+	shader->pos_attrib = glGetAttribLocation(prog, "pos");
+	shader->tex_attrib = glGetAttribLocation(prog, "texcoord");
+	shader->size = glGetUniformLocation(prog, "size");
+	shader->position = glGetUniformLocation(prog, "position");
+	shader->radius = glGetUniformLocation(prog, "radius");
+	shader->saturation = glGetUniformLocation(prog, "saturation");
+	shader->has_titlebar = glGetUniformLocation(prog, "has_titlebar");
+
+	return true;
+}
+
+static bool link_rounded_quad_program(struct fx_renderer *renderer,
+		struct rounded_quad_shader *shader, enum fx_rounded_quad_shader_source source) {
+	GLchar quad_src[2048];
+	snprintf(quad_src, sizeof(quad_src),
+		"#define SOURCE %d\n%s", source, quad_round_frag_src);
+
+	GLuint prog;
+	shader->program = prog = link_program(quad_src);
+	if (!shader->program) {
+		return false;
+	}
+
+	shader->proj = glGetUniformLocation(prog, "proj");
+	shader->color = glGetUniformLocation(prog, "color");
+	shader->pos_attrib = glGetAttribLocation(prog, "pos");
+	shader->size = glGetUniformLocation(prog, "size");
+	shader->position = glGetUniformLocation(prog, "position");
+	shader->radius = glGetUniformLocation(prog, "radius");
+
+	return true;
+}
+
+static bool check_gl_ext(const char *exts, const char *ext) {
+	size_t extlen = strlen(ext);
+	const char *end = exts + strlen(exts);
+
+	while (exts < end) {
+		if (exts[0] == ' ') {
+			exts++;
+			continue;
+		}
+		size_t n = strcspn(exts, " ");
+		if (n == extlen && strncmp(ext, exts, n) == 0) {
+			return true;
+		}
+		exts += n;
+	}
+	return false;
+}
+
+static void load_gl_proc(void *proc_ptr, const char *name) {
+	void *proc = (void *)eglGetProcAddress(name);
+	if (proc == NULL) {
+		sway_log(SWAY_ERROR, "GLES2 RENDERER: eglGetProcAddress(%s) failed", name);
+		abort();
+	}
+	*(void **)proc_ptr = proc;
+}
+
+struct fx_renderer *fx_renderer_create(struct wlr_egl *egl) {
+	struct fx_renderer *renderer = calloc(1, sizeof(struct fx_renderer));
+	if (renderer == NULL) {
+		return NULL;
+	}
+
+	// TODO: wlr_egl_make_current or eglMakeCurrent?
+	// TODO: assert instead of conditional statement?
+	if (!eglMakeCurrent(wlr_egl_get_display(egl), EGL_NO_SURFACE, EGL_NO_SURFACE,
+			wlr_egl_get_context(egl))) {
+		sway_log(SWAY_ERROR, "GLES2 RENDERER: Could not make EGL current");
+		return NULL;
+	}
+	// TODO: needed?
+	renderer->egl = egl;
+
+	// get extensions
+	const char *exts_str = (const char *)glGetString(GL_EXTENSIONS);
+	if (exts_str == NULL) {
+		sway_log(SWAY_ERROR, "GLES2 RENDERER: Failed to get GL_EXTENSIONS");
+		return NULL;
+	}
+
+	sway_log(SWAY_INFO, "Creating swayfx GLES2 renderer");
+	sway_log(SWAY_INFO, "Using %s", glGetString(GL_VERSION));
+	sway_log(SWAY_INFO, "GL vendor: %s", glGetString(GL_VENDOR));
+	sway_log(SWAY_INFO, "GL renderer: %s", glGetString(GL_RENDERER));
+	sway_log(SWAY_INFO, "Supported GLES2 extensions: %s", exts_str);
+
+	// TODO: the rest of the gl checks
+	if (check_gl_ext(exts_str, "GL_OES_EGL_image_external")) {
+		renderer->exts.OES_egl_image_external = true;
+		load_gl_proc(&renderer->procs.glEGLImageTargetTexture2DOES,
+			"glEGLImageTargetTexture2DOES");
+	}
+
+	// init shaders
+	GLuint prog;
+
+	// quad fragment shader
+	prog = link_program(quad_frag_src);
+	renderer->shaders.quad.program = prog;
+	if (!renderer->shaders.quad.program) {
+		goto error;
+	}
+	renderer->shaders.quad.proj = glGetUniformLocation(prog, "proj");
+	renderer->shaders.quad.color = glGetUniformLocation(prog, "color");
+	renderer->shaders.quad.pos_attrib = glGetAttribLocation(prog, "pos");
+
+	// rounded quad fragment shaders
+	if (!link_rounded_quad_program(renderer, &renderer->shaders.rounded_quad,
+			SHADER_SOURCE_QUAD_ROUND)) {
+		goto error;
+	}
+	if (!link_rounded_quad_program(renderer, &renderer->shaders.rounded_tl_quad,
+			SHADER_SOURCE_QUAD_ROUND_TOP_LEFT)) {
+		goto error;
+	}
+	if (!link_rounded_quad_program(renderer, &renderer->shaders.rounded_tr_quad,
+			SHADER_SOURCE_QUAD_ROUND_TOP_RIGHT)) {
+		goto error;
+	}
+
+	// Border corner shader
+	prog = link_program(corner_frag_src);
+	renderer->shaders.corner.program = prog;
+	if (!renderer->shaders.corner.program) {
+		goto error;
+	}
+	renderer->shaders.corner.proj = glGetUniformLocation(prog, "proj");
+	renderer->shaders.corner.color = glGetUniformLocation(prog, "color");
+	renderer->shaders.corner.pos_attrib = glGetAttribLocation(prog, "pos");
+	renderer->shaders.corner.is_top_left = glGetUniformLocation(prog, "is_top_left");
+	renderer->shaders.corner.is_top_right = glGetUniformLocation(prog, "is_top_right");
+	renderer->shaders.corner.is_bottom_left = glGetUniformLocation(prog, "is_bottom_left");
+	renderer->shaders.corner.is_bottom_right = glGetUniformLocation(prog, "is_bottom_right");
+	renderer->shaders.corner.position = glGetUniformLocation(prog, "position");
+	renderer->shaders.corner.radius = glGetUniformLocation(prog, "radius");
+	renderer->shaders.corner.half_size = glGetUniformLocation(prog, "half_size");
+	renderer->shaders.corner.half_thickness = glGetUniformLocation(prog, "half_thickness");
+
+	// box shadow shader
+	prog = link_program(box_shadow_frag_src);
+	renderer->shaders.box_shadow.program = prog;
+	if (!renderer->shaders.box_shadow.program) {
+		goto error;
+	}
+	renderer->shaders.box_shadow.proj = glGetUniformLocation(prog, "proj");
+	renderer->shaders.box_shadow.color = glGetUniformLocation(prog, "color");
+	renderer->shaders.box_shadow.pos_attrib = glGetAttribLocation(prog, "pos");
+	renderer->shaders.box_shadow.position = glGetUniformLocation(prog, "position");
+	renderer->shaders.box_shadow.size = glGetUniformLocation(prog, "size");
+	renderer->shaders.box_shadow.blur_sigma = glGetUniformLocation(prog, "blur_sigma");
+	renderer->shaders.box_shadow.corner_radius = glGetUniformLocation(prog, "corner_radius");
+
+	// fragment shaders
+	if (!link_tex_program(renderer, &renderer->shaders.tex_rgba,
+			SHADER_SOURCE_TEXTURE_RGBA)) {
+		goto error;
+	}
+	if (!link_tex_program(renderer, &renderer->shaders.tex_rgbx,
+			SHADER_SOURCE_TEXTURE_RGBX)) {
+		goto error;
+	}
+	if (!link_tex_program(renderer, &renderer->shaders.tex_ext,
+			SHADER_SOURCE_TEXTURE_EXTERNAL)) {
+		goto error;
+	}
+
+
+	if (!eglMakeCurrent(wlr_egl_get_display(renderer->egl),
+				EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT)) {
+		sway_log(SWAY_ERROR, "GLES2 RENDERER: Could not unset current EGL");
+		goto error;
+	}
+
+	sway_log(SWAY_INFO, "GLES2 RENDERER: Shaders Initialized Successfully");
+	return renderer;
+
+error:
+	glDeleteProgram(renderer->shaders.quad.program);
+	glDeleteProgram(renderer->shaders.rounded_quad.program);
+	glDeleteProgram(renderer->shaders.rounded_tl_quad.program);
+	glDeleteProgram(renderer->shaders.rounded_tr_quad.program);
+	glDeleteProgram(renderer->shaders.corner.program);
+	glDeleteProgram(renderer->shaders.box_shadow.program);
+	glDeleteProgram(renderer->shaders.tex_rgba.program);
+	glDeleteProgram(renderer->shaders.tex_rgbx.program);
+	glDeleteProgram(renderer->shaders.tex_ext.program);
+
+	if (!eglMakeCurrent(wlr_egl_get_display(renderer->egl),
+				EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT)) {
+		sway_log(SWAY_ERROR, "GLES2 RENDERER: Could not unset current EGL");
+	}
+
+	// TODO: more freeing?
+	free(renderer);
+
+	sway_log(SWAY_ERROR, "GLES2 RENDERER: Error Initializing Shaders");
+	return NULL;
+}
+
+void fx_renderer_begin(struct fx_renderer *renderer, uint32_t width, uint32_t height) {
+	// Create and render the stencil buffer
+	if (renderer->stencil_buffer_id == 0) {
+		glGenRenderbuffers(1, &renderer->stencil_buffer_id);
+	}
+	glBindRenderbuffer(GL_RENDERBUFFER, renderer->stencil_buffer_id);
+	glRenderbufferStorage(GL_RENDERBUFFER, GL_STENCIL_INDEX8, width, height);
+	glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_STENCIL_ATTACHMENT,
+			GL_RENDERBUFFER, renderer->stencil_buffer_id);
+
+	glViewport(0, 0, width, height);
+
+	// refresh projection matrix
+	matrix_projection(renderer->projection, width, height,
+		WL_OUTPUT_TRANSFORM_FLIPPED_180);
+
+	glBlendFunc(GL_ONE, GL_ONE_MINUS_SRC_ALPHA);
+}
+
+void fx_renderer_end() {
+	// TODO
+}
+
+void fx_renderer_clear(const float color[static 4]) {
+	glClearColor(color[0], color[1], color[2], color[3]);
+	glClearStencil(0);
+	glClear(GL_COLOR_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
+}
+
+void fx_renderer_scissor(struct wlr_box *box) {
+		if (box) {
+				glScissor(box->x, box->y, box->width, box->height);
+				glEnable(GL_SCISSOR_TEST);
+		} else {
+				glDisable(GL_SCISSOR_TEST);
+		}
+}
+
+bool fx_render_subtexture_with_matrix(struct fx_renderer *renderer, struct wlr_texture *wlr_texture,
+		const struct wlr_fbox *src_box, const struct wlr_box *dst_box, const float matrix[static 9],
+		struct decoration_data deco_data) {
+	assert(wlr_texture_is_gles2(wlr_texture));
+	struct wlr_gles2_texture_attribs texture_attrs;
+	wlr_gles2_texture_get_attribs(wlr_texture, &texture_attrs);
+
+	struct gles2_tex_shader *shader = NULL;
+
+	switch (texture_attrs.target) {
+	case GL_TEXTURE_2D:
+		if (texture_attrs.has_alpha) {
+			shader = &renderer->shaders.tex_rgba;
+		} else {
+			shader = &renderer->shaders.tex_rgbx;
+		}
+		break;
+	case GL_TEXTURE_EXTERNAL_OES:
+		shader = &renderer->shaders.tex_ext;
+
+		if (!renderer->exts.OES_egl_image_external) {
+			sway_log(SWAY_ERROR, "Failed to render texture: "
+				"GL_TEXTURE_EXTERNAL_OES not supported");
+			return false;
+		}
+		break;
+	default:
+		sway_log(SWAY_ERROR, "Aborting render");
+		abort();
+	}
+
+	float gl_matrix[9];
+	wlr_matrix_multiply(gl_matrix, renderer->projection, matrix);
+
+	// OpenGL ES 2 requires the glUniformMatrix3fv transpose parameter to be set
+	// to GL_FALSE
+	wlr_matrix_transpose(gl_matrix, gl_matrix);
+
+	// if there's no opacity or rounded corners we don't need to blend
+	if (!texture_attrs.has_alpha && deco_data.alpha == 1.0 && !deco_data.corner_radius) {
+		glDisable(GL_BLEND);
+	} else {
+		glEnable(GL_BLEND);
+	}
+
+	glActiveTexture(GL_TEXTURE0);
+	glBindTexture(texture_attrs.target, texture_attrs.tex);
+
+	glTexParameteri(texture_attrs.target, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+
+	glUseProgram(shader->program);
+
+	float* dim_color = deco_data.dim_color;
+
+	glUniformMatrix3fv(shader->proj, 1, GL_FALSE, gl_matrix);
+	glUniform1i(shader->tex, 0);
+	glUniform2f(shader->size, dst_box->width, dst_box->height);
+	glUniform2f(shader->position, dst_box->x, dst_box->y);
+	glUniform1f(shader->alpha, deco_data.alpha);
+	glUniform1f(shader->dim, deco_data.dim);
+	glUniform4f(shader->dim_color, dim_color[0], dim_color[1], dim_color[2], dim_color[3]);
+	glUniform1f(shader->has_titlebar, deco_data.has_titlebar);
+	glUniform1f(shader->saturation, deco_data.saturation);
+	glUniform1f(shader->radius, deco_data.corner_radius);
+
+	const GLfloat x1 = src_box->x / wlr_texture->width;
+	const GLfloat y1 = src_box->y / wlr_texture->height;
+	const GLfloat x2 = (src_box->x + src_box->width) / wlr_texture->width;
+	const GLfloat y2 = (src_box->y + src_box->height) / wlr_texture->height;
+	const GLfloat texcoord[] = {
+		x2, y1, // top right
+		x1, y1, // top left
+		x2, y2, // bottom right
+		x1, y2, // bottom left
+	};
+
+	glVertexAttribPointer(shader->pos_attrib, 2, GL_FLOAT, GL_FALSE, 0, verts);
+	glVertexAttribPointer(shader->tex_attrib, 2, GL_FLOAT, GL_FALSE, 0, texcoord);
+
+	glEnableVertexAttribArray(shader->pos_attrib);
+	glEnableVertexAttribArray(shader->tex_attrib);
+
+	glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
+
+	glDisableVertexAttribArray(shader->pos_attrib);
+	glDisableVertexAttribArray(shader->tex_attrib);
+
+	glBindTexture(texture_attrs.target, 0);
+
+	return true;
+}
+
+bool fx_render_texture_with_matrix(struct fx_renderer *renderer, struct wlr_texture *wlr_texture,
+		const struct wlr_box *dst_box, const float matrix[static 9],
+		struct decoration_data deco_data) {
+	struct wlr_fbox src_box = {
+		.x = 0,
+		.y = 0,
+		.width = wlr_texture->width,
+		.height = wlr_texture->height,
+	};
+	return fx_render_subtexture_with_matrix(renderer, wlr_texture, &src_box,
+			dst_box, matrix, deco_data);
+}
+
+void fx_render_rect(struct fx_renderer *renderer, const struct wlr_box *box,
+		const float color[static 4], const float projection[static 9]) {
+	if (box->width == 0 || box->height == 0) {
+		return;
+	}
+	assert(box->width > 0 && box->height > 0);
+	float matrix[9];
+	wlr_matrix_project_box(matrix, box, WL_OUTPUT_TRANSFORM_NORMAL, 0, projection);
+
+	float gl_matrix[9];
+	wlr_matrix_multiply(gl_matrix, renderer->projection, matrix);
+
+	// TODO: investigate why matrix is flipped prior to this cmd
+	// wlr_matrix_multiply(gl_matrix, flip_180, gl_matrix);
+
+	wlr_matrix_transpose(gl_matrix, gl_matrix);
+
+	if (color[3] == 1.0) {
+		glDisable(GL_BLEND);
+	} else {
+		glEnable(GL_BLEND);
+	}
+
+	glUseProgram(renderer->shaders.quad.program);
+
+	glUniformMatrix3fv(renderer->shaders.quad.proj, 1, GL_FALSE, gl_matrix);
+	glUniform4f(renderer->shaders.quad.color, color[0], color[1], color[2], color[3]);
+
+	glVertexAttribPointer(renderer->shaders.quad.pos_attrib, 2, GL_FLOAT, GL_FALSE,
+			0, verts);
+
+	glEnableVertexAttribArray(renderer->shaders.quad.pos_attrib);
+
+	glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
+
+	glDisableVertexAttribArray(renderer->shaders.quad.pos_attrib);
+}
+
+void fx_render_rounded_rect(struct fx_renderer *renderer, const struct wlr_box *box,
+		const float color[static 4], const float projection[static 9],
+		int radius, enum corner_location corner_location) {
+	if (box->width == 0 || box->height == 0) {
+		return;
+	}
+	assert(box->width > 0 && box->height > 0);
+
+	struct rounded_quad_shader *shader = NULL;
+
+	switch (corner_location) {
+		case ALL:
+			shader = &renderer->shaders.rounded_quad;
+			break;
+		case TOP_LEFT:
+			shader = &renderer->shaders.rounded_tl_quad;
+			break;
+		case TOP_RIGHT:
+			shader = &renderer->shaders.rounded_tr_quad;
+			break;
+		default:
+			sway_log(SWAY_ERROR, "Invalid Corner Location. Aborting render");
+			abort();
+	}
+
+	float matrix[9];
+	wlr_matrix_project_box(matrix, box, WL_OUTPUT_TRANSFORM_NORMAL, 0, projection);
+
+	float gl_matrix[9];
+	wlr_matrix_multiply(gl_matrix, renderer->projection, matrix);
+
+	// TODO: investigate why matrix is flipped prior to this cmd
+	// wlr_matrix_multiply(gl_matrix, flip_180, gl_matrix);
+
+	wlr_matrix_transpose(gl_matrix, gl_matrix);
+
+	glEnable(GL_BLEND);
+
+	glUseProgram(shader->program);
+
+	glUniformMatrix3fv(shader->proj, 1, GL_FALSE, gl_matrix);
+	glUniform4f(shader->color, color[0], color[1], color[2], color[3]);
+
+	// rounded corners
+	glUniform2f(shader->size, box->width, box->height);
+	glUniform2f(shader->position, box->x, box->y);
+	glUniform1f(shader->radius, radius);
+
+	glVertexAttribPointer(shader->pos_attrib, 2, GL_FLOAT, GL_FALSE,
+			0, verts);
+
+	glEnableVertexAttribArray(shader->pos_attrib);
+
+	glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
+
+	glDisableVertexAttribArray(shader->pos_attrib);
+}
+
+void fx_render_border_corner(struct fx_renderer *renderer, const struct wlr_box *box,
+		const float color[static 4], const float projection[static 9],
+		enum corner_location corner_location, int radius, int border_thickness) {
+	if (border_thickness == 0 || box->width == 0 || box->height == 0) {
+		return;
+	}
+	assert(box->width > 0 && box->height > 0);
+	float matrix[9];
+	wlr_matrix_project_box(matrix, box, WL_OUTPUT_TRANSFORM_NORMAL, 0, projection);
+
+	float gl_matrix[9];
+	wlr_matrix_multiply(gl_matrix, renderer->projection, matrix);
+
+	// TODO: investigate why matrix is flipped prior to this cmd
+	// wlr_matrix_multiply(gl_matrix, flip_180, gl_matrix);
+
+	wlr_matrix_transpose(gl_matrix, gl_matrix);
+
+	if (color[3] == 1.0 && !radius) {
+		glDisable(GL_BLEND);
+	} else {
+		glEnable(GL_BLEND);
+	}
+
+	glUseProgram(renderer->shaders.corner.program);
+
+	glUniformMatrix3fv(renderer->shaders.corner.proj, 1, GL_FALSE, gl_matrix);
+	glUniform4f(renderer->shaders.corner.color, color[0], color[1], color[2], color[3]);
+
+	glUniform1f(renderer->shaders.corner.is_top_left, corner_location == TOP_LEFT);
+	glUniform1f(renderer->shaders.corner.is_top_right, corner_location == TOP_RIGHT);
+	glUniform1f(renderer->shaders.corner.is_bottom_left, corner_location == BOTTOM_LEFT);
+	glUniform1f(renderer->shaders.corner.is_bottom_right, corner_location == BOTTOM_RIGHT);
+
+	glUniform2f(renderer->shaders.corner.position, box->x, box->y);
+	glUniform1f(renderer->shaders.corner.radius, radius);
+	glUniform2f(renderer->shaders.corner.half_size, box->width / 2.0, box->height / 2.0);
+	glUniform1f(renderer->shaders.corner.half_thickness, border_thickness / 2.0);
+
+	glVertexAttribPointer(renderer->shaders.corner.pos_attrib, 2, GL_FLOAT, GL_FALSE,
+			0, verts);
+
+	glEnableVertexAttribArray(renderer->shaders.corner.pos_attrib);
+
+	glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
+
+	glDisableVertexAttribArray(renderer->shaders.corner.pos_attrib);
+}
+
+// TODO: alpha input arg?
+void fx_render_box_shadow(struct fx_renderer *renderer, const struct wlr_box *box,
+		const float color[static 4], const float projection[static 9],
+		int corner_radius, float blur_sigma) {
+	if (box->width == 0 || box->height == 0) {
+		return;
+	}
+	assert(box->width > 0 && box->height > 0);
+	float matrix[9];
+	wlr_matrix_project_box(matrix, box, WL_OUTPUT_TRANSFORM_NORMAL, 0, projection);
+
+	float gl_matrix[9];
+	wlr_matrix_multiply(gl_matrix, renderer->projection, matrix);
+
+	// TODO: investigate why matrix is flipped prior to this cmd
+	// wlr_matrix_multiply(gl_matrix, flip_180, gl_matrix);
+
+	wlr_matrix_transpose(gl_matrix, gl_matrix);
+
+	// Init stencil work
+	// NOTE: Alpha needs to be set to 1.0 to be able to discard any "empty" pixels
+	const float col[4] = {0.0, 0.0, 0.0, 1.0};
+	struct wlr_box inner_box;
+	memcpy(&inner_box, box, sizeof(struct wlr_box));
+	inner_box.x += blur_sigma;
+	inner_box.y += blur_sigma;
+	inner_box.width -= blur_sigma * 2;
+	inner_box.height -= blur_sigma * 2;
+
+	glEnable(GL_STENCIL_TEST);
+	glClearStencil(0);
+	glClear(GL_STENCIL_BUFFER_BIT);
+
+	glStencilFunc(GL_ALWAYS, 1, 0xFF);
+	glStencilOp(GL_KEEP, GL_KEEP, GL_REPLACE);
+	// Disable writing to color buffer
+	glColorMask(GL_FALSE, GL_FALSE, GL_FALSE, GL_FALSE);
+	// Draw the rounded rect as a mask
+	fx_render_rounded_rect(renderer, &inner_box, col, projection, corner_radius, ALL);
+	// Close the mask
+	glStencilFunc(GL_NOTEQUAL, 1, 0xFF);
+	glStencilOp(GL_KEEP, GL_KEEP, GL_KEEP);
+	// Reenable writing to color buffer
+	glColorMask(GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE);
+
+	// blending will practically always be needed (unless we have a madman
+	// who uses opaque shadows with zero sigma), so just enable it
+	glEnable(GL_BLEND);
+
+	glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+
+	glUseProgram(renderer->shaders.box_shadow.program);
+
+	glUniformMatrix3fv(renderer->shaders.box_shadow.proj, 1, GL_FALSE, gl_matrix);
+	glUniform4f(renderer->shaders.box_shadow.color, color[0], color[1], color[2], color[3]);
+	glUniform1f(renderer->shaders.box_shadow.blur_sigma, blur_sigma);
+	glUniform1f(renderer->shaders.box_shadow.corner_radius, corner_radius);
+
+	glUniform2f(renderer->shaders.box_shadow.size, box->width, box->height);
+	glUniform2f(renderer->shaders.box_shadow.position, box->x, box->y);
+
+	glVertexAttribPointer(renderer->shaders.box_shadow.pos_attrib, 2, GL_FLOAT, GL_FALSE,
+			0, verts);
+
+	glEnableVertexAttribArray(renderer->shaders.box_shadow.pos_attrib);
+
+	glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
+
+	glDisableVertexAttribArray(renderer->shaders.box_shadow.pos_attrib);
+
+	glBlendFunc(GL_ONE, GL_ONE_MINUS_SRC_ALPHA);
+
+	glClearStencil(0);
+	glClear(GL_STENCIL_BUFFER_BIT);
+	glDisable(GL_STENCIL_TEST);
+}