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authorLudovic Pouzenc <ludovic@pouzenc.fr>2019-09-15 12:36:19 +0200
committerLudovic Pouzenc <ludovic@pouzenc.fr>2019-09-15 12:36:19 +0200
commitb6ab2f2c62e593edb50508e0b911a01fe773122f (patch)
treea049c63cc30a73bb85b1bd65a2838c8446c5c3e1 /src
parentf19afa163e5b9bc7a0dc540e3ab51f8f1ea715bf (diff)
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Unplug SDL_Renderer from OpenGL process. Use FrameBufferObject.
Diffstat (limited to 'src')
-rw-r--r--src/demoscene-eo.c2
-rw-r--r--src/main.h3
-rw-r--r--src/scene01.c60
3 files changed, 53 insertions, 12 deletions
diff --git a/src/demoscene-eo.c b/src/demoscene-eo.c
index 94db4e5..ed6fe1b 100644
--- a/src/demoscene-eo.c
+++ b/src/demoscene-eo.c
@@ -367,7 +367,7 @@ int worker_gl() {
SDL_GL_SetAttribute(SDL_GL_BLUE_SIZE, 8);
SDL_GL_SetAttribute(SDL_GL_ALPHA_SIZE, 8);
SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
- SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 2);
+ SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 3);
SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
// Initialize OpenGL
diff --git a/src/main.h b/src/main.h
index bf622ed..a8e0722 100644
--- a/src/main.h
+++ b/src/main.h
@@ -36,7 +36,8 @@ typedef struct {
// OpenGL worker
SDL_Window* gl_win;
SDL_GLContext gl_ctx;
- SDL_Renderer *gl_rndr;
+ SDL_Renderer *gl_rndr; //XXX remove me
+ GLuint gl_fbo;
SDL_Texture *gl_target;
// framebuffer to inject OpenGL or SDL result in caca canvas
uint32_t raw_target[FBUF_W*FBUF_H];
diff --git a/src/scene01.c b/src/scene01.c
index 39083d0..a93aa3d 100644
--- a/src/scene01.c
+++ b/src/scene01.c
@@ -75,7 +75,9 @@ typedef enum t_attrib_id
} t_attrib_id;
int scene01_init_gl(graphical_env_t *ge, scene01_env_t *se) {
- GLuint vs, fs, program;
+ GLuint vs, fs, program, vbo, renderedTexture, depthrenderbuffer;
+ GLint status;
+ GLenum DrawBuffers[1] = {GL_COLOR_ATTACHMENT0};
TRACE("call");
vs = glCreateShader(GL_VERTEX_SHADER);
@@ -85,7 +87,6 @@ int scene01_init_gl(graphical_env_t *ge, scene01_env_t *se) {
glShaderSource(vs, 1, (const GLchar **)&vertex_shader, &length);
glCompileShader(vs);
- GLint status;
glGetShaderiv(vs, GL_COMPILE_STATUS, &status);
if(status == GL_FALSE) return 40;
@@ -106,12 +107,45 @@ int scene01_init_gl(graphical_env_t *ge, scene01_env_t *se) {
glUseProgram(program);
+ // http://www.opengl-tutorial.org/intermediate-tutorials/tutorial-14-render-to-texture/
+
+ // The framebuffer, which regroups 0, 1, or more textures, and 0 or 1 depth buffer.
+ glGenFramebuffers(1, &ge->gl_fbo);
+
+ // The texture we're going to render to
+ glGenTextures(1, &renderedTexture);
+
+ // "Bind" the newly created texture : all future texture functions will modify this texture
+ glBindTexture(GL_TEXTURE_2D, renderedTexture);
+
+ // Give an empty image to OpenGL ( the last "0" )
+ glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, FBUF_W, FBUF_H, 0, GL_RGB, GL_UNSIGNED_BYTE, 0);
+
+ // Poor filtering. Needed !
+ glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+ glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+
+ // The depth buffer
+ glGenRenderbuffers(1, &depthrenderbuffer);
+ glBindRenderbuffer(GL_RENDERBUFFER, depthrenderbuffer);
+ glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT, FBUF_W, FBUF_H);
+ glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, depthrenderbuffer);
+
+ // Set "renderedTexture" as our colour attachement #0
+ glFramebufferTexture(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, renderedTexture, 0);
+
+ // Set the list of draw buffers.
+ glDrawBuffers(1, DrawBuffers); // "1" is the size of DrawBuffers
+
+ // Always check that our framebuffer is ok
+ if(glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE) {
+ return 1;
+ }
+
glDisable(GL_DEPTH_TEST);
- glClearColor(0.5, 0.0, 0.0, 0.0);
+ //glClearColor(0.5, 0.0, 0.0, 0.0);
glViewport(0, 0, FBUF_W, FBUF_H);
- GLuint vbo;
-
glGenVertexArrays(1, &(se->vao));
glGenBuffers(1, &vbo);
glBindVertexArray(se->vao);
@@ -139,6 +173,8 @@ int scene01_init_gl(graphical_env_t *ge, scene01_env_t *se) {
t_mat4x4 projection_matrix;
mat4x4_ortho(projection_matrix, 0.0f, (float)FBUF_W, (float)FBUF_H, 0.0f, 0.0f, 100.0f);
glUniformMatrix4fv(glGetUniformLocation(program, "u_projection_matrix"), 1, GL_FALSE, projection_matrix);
+
+
return 0;
}
@@ -166,21 +202,25 @@ void scene01_free_caca(graphical_env_t *ge, scene01_env_t *se) {
}
int scene01_next_gl(graphical_env_t *ge, scene01_env_t *se) {
- SDL_Renderer *r = ge->gl_rndr;
TRACE_CALL_ONCE;
- // https://gist.github.com/Twinklebear/8265888
- // https://forums.libsdl.org/viewtopic.php?p=51634
+ // Render to the in-VRAM Framebuffer Object
+ glBindFramebuffer(GL_FRAMEBUFFER, ge->gl_fbo);
glClear(GL_COLOR_BUFFER_BIT);
glBindVertexArray(se->vao);
glDrawArrays(GL_TRIANGLES, 0, 6);
// [...]
- //SDL_GL_SwapWindow(ge->gl_win);
+ // Render to the screen
+ glBindFramebuffer(GL_FRAMEBUFFER, 0);
+ glClear(GL_COLOR_BUFFER_BIT);
+ glBindVertexArray(se->vao);
+ glDrawArrays(GL_TRIANGLES, 0, 6);
+ SDL_GL_SwapWindow(ge->gl_win);
// Download the rendered texture from videocard to main memory
- SDL_RenderReadPixels(r, NULL, 0, ge->raw_target, FBUF_W*4);
+ //SDL_RenderReadPixels(r, NULL, 0, ge->raw_target, FBUF_W*4);
return 0;
}