gdk_gl_texture_quad: Use shaders to texture things

This is the modern way OpenGL works, and using it will let us
switch to a core context for the paint context, and work on
OpenGL ES 2.0.
This commit is contained in:
Alexander Larsson 2014-11-06 09:13:36 +01:00
parent c78e7e7f17
commit e417b18373
4 changed files with 194 additions and 15 deletions

View File

@ -35,25 +35,193 @@ gdk_cairo_surface_mark_as_direct (cairo_surface_t *surface,
g_object_ref (window), g_object_unref);
}
static const char *
get_vertex_type_name (int type)
{
switch (type)
{
case GL_VERTEX_SHADER:
return "vertex";
case GL_GEOMETRY_SHADER:
return "geometry";
case GL_FRAGMENT_SHADER:
return "fragment";
}
return "unknown";
}
guint
create_shader (int type, const char const *code)
{
guint shader;
int status;
shader = glCreateShader (type);
glShaderSource (shader, 1, &code, NULL);
glCompileShader (shader);
glGetShaderiv (shader, GL_COMPILE_STATUS, &status);
if (status == GL_FALSE)
{
int log_len;
char *buffer;
glGetShaderiv (shader, GL_INFO_LOG_LENGTH, &log_len);
buffer = g_malloc (log_len + 1);
glGetShaderInfoLog (shader, log_len, NULL, buffer);
g_warning ("Compile failure in %s shader:\n%s\n", get_vertex_type_name (type), buffer);
g_free (buffer);
glDeleteShader (shader);
return 0;
}
return shader;
}
guint
make_program (const char const *vertex_shader_code, const char const *fragment_shader_code)
{
guint program, vertex_shader, fragment_shader;
int status;
vertex_shader = create_shader (GL_VERTEX_SHADER, vertex_shader_code);
if (vertex_shader == 0)
return 0;
fragment_shader = create_shader (GL_FRAGMENT_SHADER, fragment_shader_code);
if (fragment_shader == 0)
{
glDeleteShader (vertex_shader);
return 0;
}
program = glCreateProgram ();
glAttachShader (program, vertex_shader);
glAttachShader (program, fragment_shader);
glLinkProgram (program);
glDeleteShader (vertex_shader);
glDeleteShader (fragment_shader);
glGetProgramiv (program, GL_LINK_STATUS, &status);
if (status == GL_FALSE)
{
int log_len;
char *buffer;
glGetProgramiv (program, GL_INFO_LOG_LENGTH, &log_len);
buffer = g_malloc (log_len + 1);
glGetProgramInfoLog (program, log_len, NULL, buffer);
g_warning ("Linker failure: %s\n", buffer);
g_free (buffer);
glDeleteProgram (program);
return 0;
}
return program;
}
static void
bind_vao (GdkGLContextPaintData *paint_data)
{
if (paint_data->vertex_array_object == 0)
{
glGenVertexArrays (1, &paint_data->vertex_array_object);
/* ATM we only use one VAO, so always bind it */
glBindVertexArray (paint_data->vertex_array_object);
}
}
static void
use_texture_program (GdkGLContextPaintData *paint_data)
{
const char *vertex_shader_code =
"#version 120\n"
"uniform sampler2D map;"
"attribute vec2 position;\n"
"attribute vec2 uv;\n"
"varying vec2 vUv;\n"
"void main() {\n"
" gl_Position = vec4(position, 0, 1);\n"
" vUv = uv;\n"
"}\n";
const char *fragment_shader_code =
"#version 120\n"
"varying vec2 vUv;\n"
"uniform sampler2D map;\n"
"void main() {\n"
" gl_FragColor = texture2D (map, vUv);\n"
"}\n";
if (paint_data->texture_quad_program == 0)
{
paint_data->texture_quad_program = make_program (vertex_shader_code, fragment_shader_code);
paint_data->texture_quad_program_position_location = glGetAttribLocation (paint_data->texture_quad_program, "position");
paint_data->texture_quad_program_uv_location = glGetAttribLocation (paint_data->texture_quad_program, "uv");
}
if (paint_data->current_program != paint_data->texture_quad_program)
{
glUseProgram (paint_data->texture_quad_program);
paint_data->current_program = paint_data->texture_quad_program;
}
}
void
gdk_gl_texture_quad (float x1, float y1,
gdk_gl_texture_quad (GdkGLContext *paint_context,
float x1, float y1,
float x2, float y2,
float u1, float v1,
float u2, float v2)
{
glBegin (GL_QUADS);
glTexCoord2f (u1, v2);
glVertex2f (x1, y2);
GdkGLContextPaintData *paint_data = gdk_gl_context_get_paint_data (paint_context);;
GdkWindow *window = gdk_gl_context_get_window (paint_context);
float w = gdk_window_get_width (window);
float h = gdk_window_get_height (window);
float vertex_buffer_data[] = {
(x2 * 2) / w - 1, (y1 * 2) / h - 1,
(x2 * 2) / w - 1, (y2 * 2) / h - 1,
(x1 * 2) / w - 1, (y2 * 2) / h - 1,
(x1 * 2) / w - 1, (y1 * 2) / h - 1,
};
float uv_buffer_data[] = {
u2, v1,
u2, v2,
u1, v2,
u1, v1,
};
glTexCoord2f (u2, v2);
glVertex2f (x2, y2);
bind_vao (paint_data);
glTexCoord2f (u2, v1);
glVertex2f (x2, y1);
if (paint_data->tmp_vertex_buffer == 0)
glGenBuffers(1, &paint_data->tmp_vertex_buffer);
glTexCoord2f (u1, v1);
glVertex2f (x1, y1);
glEnd();
if (paint_data->tmp_uv_buffer == 0)
glGenBuffers(1, &paint_data->tmp_uv_buffer);
use_texture_program (paint_data);
glActiveTexture (GL_TEXTURE0);
glEnableVertexAttribArray (0);
glBindBuffer (GL_ARRAY_BUFFER, paint_data->tmp_vertex_buffer);
glBufferData (GL_ARRAY_BUFFER, sizeof(vertex_buffer_data), vertex_buffer_data, GL_STREAM_DRAW);
glVertexAttribPointer (paint_data->texture_quad_program_position_location,
2, GL_FLOAT, GL_FALSE, 0, NULL);
glEnableVertexAttribArray (1);
glBindBuffer (GL_ARRAY_BUFFER, paint_data->tmp_uv_buffer);
glBufferData (GL_ARRAY_BUFFER, sizeof(uv_buffer_data), uv_buffer_data, GL_STREAM_DRAW);
glVertexAttribPointer (paint_data->texture_quad_program_uv_location,
2, GL_FLOAT, GL_FALSE, 0, NULL);
glDrawArrays (GL_TRIANGLE_FAN, 0, 4);
glDisableVertexAttribArray (0);
glDisableVertexAttribArray (1);
}
@ -328,7 +496,8 @@ gdk_cairo_draw_from_gl (cairo_t *cr,
int clipped_src_x = x + (dest.x - dx * window_scale);
int clipped_src_y = y + (height - dest.height - (dest.y - dy * window_scale));
gdk_gl_texture_quad (dest.x, FLIP_Y(dest.y),
gdk_gl_texture_quad (paint_context,
dest.x, FLIP_Y(dest.y),
dest.x + dest.width, FLIP_Y(dest.y + dest.height),
clipped_src_x / (float)texture_width, (clipped_src_y + dest.height) / (float)texture_height,
(clipped_src_x + dest.width) / (float)texture_width, clipped_src_y / (float)texture_height);
@ -507,7 +676,8 @@ gdk_gl_texture_from_surface (cairo_surface_t *surface,
vmax = 1.0;
}
gdk_gl_texture_quad (rect.x * window_scale, FLIP_Y(rect.y) * window_scale,
gdk_gl_texture_quad (paint_context,
rect.x * window_scale, FLIP_Y(rect.y) * window_scale,
(rect.x + rect.width) * window_scale, FLIP_Y(rect.y + rect.height) * window_scale,
0, 0,
umax, vmax);

View File

@ -57,7 +57,14 @@ void gdk_gl_context_end_frame (GdkGLContext *context,
typedef struct {
guint vertex_array_object;
guint tmp_framebuffer;
guint tmp_vertex_buffer;
guint tmp_uv_buffer;
guint current_program;
guint texture_quad_program;
guint texture_quad_program_position_location;
guint texture_quad_program_uv_location;
} GdkGLContextPaintData;
GdkGLContextPaintData *gdk_gl_context_get_paint_data (GdkGLContext *context);

View File

@ -341,7 +341,8 @@ gboolean _gdk_cairo_surface_extents (cairo_surface_t *surface,
GdkRectangle *extents);
void gdk_gl_texture_from_surface (cairo_surface_t *surface,
cairo_region_t *region);
void gdk_gl_texture_quad (float x1, float y1,
void gdk_gl_texture_quad (GdkGLContext *paint_context,
float x1, float y1,
float x2, float y2,
float u1, float v1,
float u2, float v2);

View File

@ -466,7 +466,8 @@ gdk_x11_gl_context_texture_from_surface (GdkGLContext *paint_context,
vscale = 1.0 / cairo_xlib_surface_get_height (surface);
}
gdk_gl_texture_quad (rect.x * window_scale, FLIP_Y(rect.y) * window_scale,
gdk_gl_texture_quad (paint_context,
rect.x * window_scale, FLIP_Y(rect.y) * window_scale,
(rect.x + rect.width) * window_scale, FLIP_Y(rect.y + rect.height) * window_scale,
uscale * src_x, vscale * src_y,
uscale * (src_x + src_width), vscale * (src_y + src_height));