Fix AMD single monitor rotated display being rotated in recording

If there is only one monitor connected and it's rotated then
the drm buf will also be rotated. This only the case with AMD and
only when using one monitor!

To fix this, we perform color conversion with an opengl shader
which allows us to also rotate the texture.
VAAPI supports rotation but it's not implemented by AMD at least.

Performance seems to be the same as when using VAAPI, even when
GPU usage is 100%.

1 files changed, 235 insertions, 0 deletions

diff --git a/src/color_conversion.c b/src/color_conversion.c
new file mode 100644
index 0000000..fbbe9e6
--- /dev/null
+++ b/src/color_conversion.c
@@ -0,0 +1,235 @@
+#include "../include/color_conversion.h"
+#include <stdio.h>
+#include <string.h>
+#include <assert.h>
+
+#define MAX_SHADERS 2
+#define MAX_FRAMEBUFFERS 2
+
+#define ROTATE_Z   "mat4 rotate_z(in float angle) {\n"                        \
+                   "    return mat4(cos(angle), -sin(angle), 0.0, 0.0,\n"     \
+                   "                sin(angle),  cos(angle), 0.0, 0.0,\n"     \
+                   "                0.0,           0.0,      1.0, 0.0,\n"     \
+                   "                0.0,           0.0,      0.0, 1.0);\n"    \
+                   "}\n"
+
+#define RGB_TO_YUV "const mat4 RGBtoYUV = mat4(0.257,  0.439, -0.148, 0.0,\n" \
+                   "                           0.504, -0.368, -0.291, 0.0,\n" \
+                   "                           0.098, -0.071,  0.439, 0.0,\n" \
+                   "                           0.0625, 0.500,  0.500, 1.0);"
+
+static int load_shader_y(gsr_shader *shader, gsr_egl *egl, float rotation) {
+    char vertex_shader[2048];
+    snprintf(vertex_shader, sizeof(vertex_shader),
+        "#version 300 es                                   \n"
+        "in vec2 pos;                                      \n"
+        "in vec2 texcoords;                                \n"
+        "out vec2 texcoords_out;                           \n"
+        ROTATE_Z
+		"void main()                                       \n"
+		"{                                                 \n"
+        "  texcoords_out = texcoords;                      \n"
+		"  gl_Position = vec4(pos.x, pos.y, 0.0, 1.0) * rotate_z(%f);    \n"
+		"}                                                 \n", rotation);
+
+    char fragment_shader[] =
+        "#version 300 es                                                                 \n"
+		"precision mediump float;                                                        \n"
+        "in vec2 texcoords_out;                                                          \n"
+        "uniform sampler2D tex1;                                                         \n"
+        "out vec4 FragColor;                                                             \n"
+        RGB_TO_YUV
+		"void main()                                                                     \n"
+		"{                                                                               \n"
+        "  FragColor.x = (RGBtoYUV * vec4(texture(tex1, texcoords_out).rgb, 1.0)).x;     \n"
+		"}                                                                               \n";
+
+    if(gsr_shader_init(shader, egl, vertex_shader, fragment_shader) != 0)
+        return -1;
+
+    gsr_shader_bind_attribute_location(shader, "pos", 0);
+    gsr_shader_bind_attribute_location(shader, "texcoords", 1);
+	return 0;
+}
+
+static unsigned int load_shader_uv(gsr_shader *shader, gsr_egl *egl, float rotation) {
+    char vertex_shader[2048];
+    snprintf(vertex_shader, sizeof(vertex_shader),
+        "#version 300 es                                 \n"
+        "in vec2 pos;                                    \n"
+        "in vec2 texcoords;                              \n"
+        "out vec2 texcoords_out;                         \n"
+        ROTATE_Z
+		"void main()                                     \n"
+		"{                                               \n"
+        "  texcoords_out = texcoords;                    \n"
+		"  gl_Position = vec4(pos.x, pos.y, 0.0, 1.0) * rotate_z(%f) * vec4(0.5, 0.5, 1.0, 1.0) - vec4(0.5, 0.5, 0.0, 0.0);   \n"
+		"}                                               \n", rotation);
+
+    char fragment_shader[] =
+        "#version 300 es                                                                       \n"
+		"precision mediump float;                                                              \n"
+        "in vec2 texcoords_out;                                                                \n"
+        "uniform sampler2D tex1;                                                               \n"
+        "out vec4 FragColor;                                                                   \n"
+        RGB_TO_YUV
+		"void main()                                                                           \n"
+		"{                                                                                     \n"
+        "  FragColor.xy = (RGBtoYUV * vec4(texture(tex1, texcoords_out).rgb, 1.0)).zy;         \n"
+		"}                                                                                     \n";
+
+    if(gsr_shader_init(shader, egl, vertex_shader, fragment_shader) != 0)
+        return -1;
+
+    gsr_shader_bind_attribute_location(shader, "pos", 0);
+    gsr_shader_bind_attribute_location(shader, "texcoords", 1);
+	return 0;
+}
+
+static int loader_framebuffers(gsr_color_conversion *self) {
+    const unsigned int draw_buffer = GL_COLOR_ATTACHMENT0;
+    self->egl->glGenFramebuffers(MAX_FRAMEBUFFERS, self->framebuffers);
+
+    self->egl->glBindFramebuffer(GL_FRAMEBUFFER, self->framebuffers[0]);
+    self->egl->glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, self->destination_textures[0], 0);
+    self->egl->glDrawBuffers(1, &draw_buffer);
+    if(self->egl->glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE) {
+        fprintf(stderr, "gsr error: gsr_color_conversion_init: failed to create framebuffer for Y\n");
+        goto err;
+    }
+
+    self->egl->glBindFramebuffer(GL_FRAMEBUFFER, self->framebuffers[1]);
+    self->egl->glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, self->destination_textures[1], 0);
+    self->egl->glDrawBuffers(1, &draw_buffer);
+    if(self->egl->glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE) {
+        fprintf(stderr, "gsr error: gsr_color_conversion_init: failed to create framebuffer for UV\n");
+        goto err;
+    }
+
+    self->egl->glBindFramebuffer(GL_FRAMEBUFFER, 0);
+    return 0;
+
+    err:
+    self->egl->glBindFramebuffer(GL_FRAMEBUFFER, 0);
+    return -1;
+}
+
+static int create_vertices(gsr_color_conversion *self, vec2f position, vec2f size) {
+    const float vertices[] = {
+        -1.0f,  1.0f,  position.x,          position.y + size.y,
+        -1.0f, -1.0f,  position.x,          position.y,
+        1.0f, -1.0f,   position.x + size.x, position.y,
+
+        -1.0f,  1.0f,  position.x,          position.y + size.y,
+        1.0f, -1.0f,   position.x + size.x, position.y,
+        1.0f,  1.0f,   position.x + size.x, position.y + size.y
+    };
+
+    self->egl->glGenVertexArrays(1, &self->vertex_array_object_id);
+    self->egl->glGenBuffers(1, &self->vertex_buffer_object_id);
+    self->egl->glBindVertexArray(self->vertex_array_object_id);
+    self->egl->glBindBuffer(GL_ARRAY_BUFFER, self->vertex_buffer_object_id);
+    self->egl->glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), &vertices, GL_STATIC_DRAW);
+
+    self->egl->glEnableVertexAttribArray(0);
+    self->egl->glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 4 * sizeof(float), (void*)0);
+
+    self->egl->glEnableVertexAttribArray(1);
+    self->egl->glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 4 * sizeof(float), (void*)(2 * sizeof(float)));
+
+    self->egl->glBindVertexArray(0);
+    return 0;
+}
+
+int gsr_color_conversion_init(gsr_color_conversion *self, const gsr_color_conversion_params *params) {
+    assert(params);
+    assert(params->egl);
+    memset(self, 0, sizeof(*self));
+    self->egl = params->egl;
+
+    if(params->num_source_textures != 1) {
+        fprintf(stderr, "gsr error: gsr_color_conversion_init: expected 1 source texture for source color RGB, got %d source texture(s)\n", params->num_source_textures);
+        return -1;
+    }
+
+    if(params->num_destination_textures != 2) {
+        fprintf(stderr, "gsr error: gsr_color_conversion_init: expected 2 destination textures for destination color NV12, got %d destination texture(s)\n", params->num_destination_textures);
+        return -1;
+    }
+
+    if(load_shader_y(&self->shaders[0], self->egl, params->rotation) != 0) {
+        fprintf(stderr, "gsr error: gsr_color_conversion_init: failed to loader Y shader\n");
+        goto err;
+    }
+
+    if(load_shader_uv(&self->shaders[1], self->egl, params->rotation) != 0) {
+        fprintf(stderr, "gsr error: gsr_color_conversion_init: failed to loader UV shader\n");
+        goto err;
+    }
+
+    self->source_textures[0] = params->source_textures[0];
+    self->destination_textures[0] = params->destination_textures[0];
+    self->destination_textures[1] = params->destination_textures[1];
+
+    if(loader_framebuffers(self) != 0)
+        goto err;
+
+    if(create_vertices(self, params->position, params->size) != 0)
+        goto err;
+
+    return 0;
+
+    err:
+    self->egl->glBindFramebuffer(GL_FRAMEBUFFER, 0);
+    gsr_color_conversion_deinit(self);
+    return -1;
+}
+
+void gsr_color_conversion_deinit(gsr_color_conversion *self) {
+    if(self->vertex_buffer_object_id) {
+        self->egl->glDeleteBuffers(1, &self->vertex_buffer_object_id);
+        self->vertex_buffer_object_id = 0;
+    }
+
+    if(self->vertex_array_object_id) {
+        self->egl->glDeleteVertexArrays(1, &self->vertex_array_object_id);
+        self->vertex_array_object_id = 0;
+    }
+
+    self->egl->glDeleteFramebuffers(MAX_FRAMEBUFFERS, self->framebuffers);
+    for(int i = 0; i < MAX_FRAMEBUFFERS; ++i) {
+        self->framebuffers[i] = 0;
+    }
+
+    for(int i = 0; i < MAX_SHADERS; ++i) {
+        gsr_shader_deinit(&self->shaders[i]);
+    }
+}
+
+int gsr_color_conversion_update(gsr_color_conversion *self, int width, int height) {
+    self->egl->glBindVertexArray(self->vertex_array_object_id);
+    self->egl->glViewport(0, 0, width, height);
+    self->egl->glBindTexture(GL_TEXTURE_2D, self->source_textures[0]);
+
+    {
+        self->egl->glBindFramebuffer(GL_FRAMEBUFFER, self->framebuffers[0]);
+        //cap_xcomp->egl.glClear(GL_COLOR_BUFFER_BIT);
+
+        gsr_shader_use(&self->shaders[0]);
+        self->egl->glDrawArrays(GL_TRIANGLES, 0, 6);
+    }
+
+    {
+        self->egl->glBindFramebuffer(GL_FRAMEBUFFER, self->framebuffers[1]);
+        //cap_xcomp->egl.glClear(GL_COLOR_BUFFER_BIT);
+
+        gsr_shader_use(&self->shaders[1]);
+        self->egl->glDrawArrays(GL_TRIANGLES, 0, 6);
+    }
+
+    self->egl->glBindVertexArray(0);
+    gsr_shader_use_none(&self->shaders[0]);
+    self->egl->glBindTexture(GL_TEXTURE_2D, 0);
+    self->egl->glBindFramebuffer(GL_FRAMEBUFFER, 0);
+    return 0;
+}