compositor: Switch away from using VBOs and just stream the vertex data

We avoid changing uniforms for each window and it will be easier to break up
a surface into a series of rectangles.

diff --git a/compositor/compositor.c b/compositor/compositor.c
index ec0d727..e036938 100644 (file)
--- a/compositor/compositor.c
+++ b/compositor/compositor.c
@@ -363,12 +363,7 @@ static void
 wlsc_surface_draw(struct wlsc_surface *es, struct wlsc_output *output)
 {
        struct wlsc_compositor *ec = es->compositor;
-       struct wlsc_matrix tmp;
-
-       tmp = es->matrix;
-       wlsc_matrix_multiply(&tmp, &output->matrix);
-       glUniformMatrix4fv(ec->proj_uniform, 1, GL_FALSE, tmp.d);
-       glUniform1i(ec->tex_uniform, 0);
+       GLfloat vertices[4 * 4];
 
        if (es->visual == &ec->compositor.argb_visual) {
                glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
@@ -380,12 +375,31 @@ wlsc_surface_draw(struct wlsc_surface *es, struct wlsc_output *output)
                glDisable(GL_BLEND);
        }
 
+       vertices[ 0] = es->x;
+       vertices[ 1] = es->y;
+       vertices[ 2] = 0.0;
+       vertices[ 3] = 0.0;
+
+       vertices[ 4] = es->x;
+       vertices[ 5] = es->y + es->height;
+       vertices[ 6] = 0.0;
+       vertices[ 7] = 1.0;
+
+       vertices[ 8] = es->x + es->width;
+       vertices[ 9] = es->y;
+       vertices[10] = 1.0;
+       vertices[11] = 0.0;
+
+       vertices[12] = es->x + es->width;
+       vertices[13] = es->y + es->height;
+       vertices[14] = 1.0;
+       vertices[15] = 1.0;
+
        glBindTexture(GL_TEXTURE_2D, es->texture);
-       glBindBuffer(GL_ARRAY_BUFFER, ec->vbo);
-       glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE,
-                             5 * sizeof(GLfloat), NULL);
+       glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE,
+                             4 * sizeof(GLfloat), vertices);
        glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE,
-                             5 * sizeof(GLfloat), (GLfloat *) 0 + 3);
+                             4 * sizeof(GLfloat), &vertices[2]);
        glEnableVertexAttribArray(0);
        glEnableVertexAttribArray(1);
        glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
@@ -432,6 +446,9 @@ wlsc_output_repaint(struct wlsc_output *output)
 
        glViewport(0, 0, output->width, output->height);
 
+       glUniformMatrix4fv(ec->proj_uniform, 1, GL_FALSE, output->matrix.d);
+       glUniform1i(ec->tex_uniform, 0);
+
        pixman_region32_init(&new_damage);
        pixman_region32_init(&total_damage);
        pixman_region32_intersect_rect(&new_damage,
@@ -1153,12 +1170,12 @@ wlsc_output_post_geometry(struct wl_client *client, struct wl_object *global)
 
 static const char vertex_shader[] =
        "uniform mat4 proj;\n"
-       "attribute vec4 position;\n"
+       "attribute vec2 position;\n"
        "attribute vec2 texcoord;\n"
        "varying vec2 v_texcoord;\n"
        "void main()\n"
        "{\n"
-       "   gl_Position = proj * position;\n"
+       "   gl_Position = proj * vec4(position, 0.0, 1.0);\n"
        "   v_texcoord = texcoord;\n"
        "}\n";
 
@@ -1177,7 +1194,6 @@ init_shaders(struct wlsc_compositor *ec)
        GLuint v, f, program;
        const char *p;
        char msg[512];
-       GLfloat vertices[4 * 5];
        GLint status;
 
        p = vertex_shader;
@@ -1220,34 +1236,6 @@ init_shaders(struct wlsc_compositor *ec)
        ec->proj_uniform = glGetUniformLocation(program, "proj");
        ec->tex_uniform = glGetUniformLocation(program, "tex");
 
-       vertices[ 0] = 0.0;
-       vertices[ 1] = 0.0;
-       vertices[ 2] = 0.0;
-       vertices[ 3] = 0.0;
-       vertices[ 4] = 0.0;
-
-       vertices[ 5] = 0.0;
-       vertices[ 6] = 1.0;
-       vertices[ 7] = 0.0;
-       vertices[ 8] = 0.0;
-       vertices[ 9] = 1.0;
-
-       vertices[10] = 1.0;
-       vertices[11] = 0.0;
-       vertices[12] = 0.0;
-       vertices[13] = 1.0;
-       vertices[14] = 0.0;
-
-       vertices[15] = 1.0;
-       vertices[16] = 1.0;
-       vertices[17] = 0.0;
-       vertices[18] = 1.0;
-       vertices[19] = 1.0;
-
-       glGenBuffers(1, &ec->vbo);
-       glBindBuffer(GL_ARRAY_BUFFER, ec->vbo);
-       glBufferData(GL_ARRAY_BUFFER, sizeof vertices, vertices, GL_STATIC_DRAW);
-
        return 0;
 }
 

diff --git a/compositor/compositor.h b/compositor/compositor.h
index 67d9f2a..61bb5c8 100644 (file)
--- a/compositor/compositor.h
+++ b/compositor/compositor.h
@@ -91,7 +91,7 @@ struct wlsc_compositor {
        struct wlsc_shm shm;
        EGLDisplay display;
        EGLContext context;
-       GLuint fbo, vbo;
+       GLuint fbo;
        GLuint proj_uniform, tex_uniform;
        struct wl_buffer **pointer_buffers;
        struct wl_display *wl_display;