playing with Z buffering in VGA driver

4 files changed, 45 insertions, 9 deletions

diff --git a/src/drivers/video/vga.c b/src/drivers/video/vga.c
index 9d540af..bcd4366 100644
--- a/src/drivers/video/vga.c
+++ b/src/drivers/video/vga.c
@@ -253,7 +253,7 @@ bool vga_set_mode( vga_t *vga, const vga_mode_t mode )
 	vga->mode = mode;
 	vga->mode.segment = get_frame_buffer_segment( vga );
 
-	vga->use_z_buffer = false;
+	vga_use_z_buffer( vga, false );
 
 	return true;
 }
@@ -317,7 +317,7 @@ void vga_set_pixel( vga_t *vga, const int x, const int y, const vga_color_t colo
 
 	uint8_t color_idx = get_color_index( color );
 
-	uint8_t *addr = vga->mode.segment + vga->mode.x * y + x;
+	uint8_t *addr = vga->base_addr + vga->mode.x * y + x;
 
 	*addr = color_idx;
 }	
@@ -337,14 +337,14 @@ void vga_draw_rectangle( vga_t *vga, const int x, const int y, const int w, cons
 	uint8_t color_idx = get_color_index( color );
 
 	for( int yy = y; yy < y + h; yy++ ) {
-		uint8_t *addr = vga->mode.segment + vga->mode.x * yy + x;
+		uint8_t *addr = vga->base_addr + vga->mode.x * yy + x;
 		memset( addr, color_idx, w );
 	}
 }
 
 void vga_clear_screen( vga_t *vga, const vga_color_t color )
 {
-	memset( vga->mode.segment, get_color_index( color ),
+	memset( vga->base_addr, get_color_index( color ),
 		vga->mode.x * vga->mode.y );
 }
 
@@ -385,6 +385,19 @@ void vga_wait_for_retrace( vga_t *vga )
 void vga_use_z_buffer( vga_t *vga, bool use )
 {
 	vga->use_z_buffer = use;
+
+	if( vga->use_z_buffer ) {
+		vga->base_addr = &vga->zbuffer[0];
+	} else {
+		vga->base_addr = vga->mode.segment;
+	}
 }
 
+void vga_refresh( vga_t *vga )
+{
+	if( vga->use_z_buffer ) {
+		vga_wait_for_retrace( vga );
+		memcpy( vga->mode.segment, vga->zbuffer, 65535 );
+	}
+}
 
diff --git a/src/drivers/video/vga.h b/src/drivers/video/vga.h
index 0f55f74..d15a55d 100644
--- a/src/drivers/video/vga.h
+++ b/src/drivers/video/vga.h
@@ -43,6 +43,14 @@ typedef struct {
 	vga_mode_t mode;
 	void *context;
 	bool use_z_buffer;
+	// TODO: the Z-buffer should actually be allocated dynamically
+	// depending on the current mode, for now it's a static buffer
+	// able to store the biggest resolution, being planar
+	// 320x200x8 aka 64k
+	uint8_t zbuffer[65535];
+	// stores either the address to the beginning of the segment
+	// (real mapped I/O memory or the beginning of the Z buffer
+	uint8_t *base_addr;
 } vga_t;
 
 typedef struct {
@@ -83,5 +91,6 @@ void vga_clear_screen( vga_t *vga, const vga_color_t color );
 void vga_draw_char( vga_t *vga, const unsigned char c, const int x, const int y, const vga_color_t background, const vga_color_t foreground );
 void vga_wait_for_retrace( vga_t *vga );
 void vga_use_z_buffer( vga_t *vga, bool use );
+void vga_refresh( vga_t *vga );
 
 #endif // VGA_H
diff --git a/src/gui/text_widget.c b/src/gui/text_widget.c
index 64bf161..eea2613 100644
--- a/src/gui/text_widget.c
+++ b/src/gui/text_widget.c
@@ -49,7 +49,7 @@ void text_widget_draw( void *obj, graphics_context_t *context )
 		vga_draw_char( context, *p, x + w, y + h, widget->base.background_color,
 			VGA_COLOR_WHITE );
 		w += 9;
-		if( w >= widget->base.w - 9 ) {
+		if( w >= widget->base.w - 10 ) {
 			h += 16;
 			w = 0;
 		}
diff --git a/src/kernel/kernel.c b/src/kernel/kernel.c
index 197f491..aacfcbd 100644
--- a/src/kernel/kernel.c
+++ b/src/kernel/kernel.c
@@ -139,7 +139,7 @@ void kernel_main( void )
 		// for now we are only interested in interrupts,
 		// so we let the main thread sleep instead of
 		// burning CPU..
-		kernel_halt( );
+//		kernel_halt( );
 
 		switch( global_context.mode ) {
 			case MODE_TEXT:
@@ -153,11 +153,13 @@ void kernel_main( void )
 				// wait for VGA retrace, assume drawing the desktop
 				// is fast enough to finish in time (so we don't recheck
 				// for retrace)
-				vga_wait_for_retrace( &global_context.vga );
+//				vga_wait_for_retrace( &global_context.vga );
 
 				// as vga_t is equals to the graphical context for now
 				((widget_vtable_t *)global_context.desktop.vtable)->draw( &global_context.desktop, &global_context.vga );
 
+				vga_refresh( &global_context.vga );
+
 				interrupts_enable( );
 
 				break;
@@ -242,14 +244,21 @@ static void handle_keyboard_event( keyboard_event_t *event, void *context )
 								}
 								*p = '\0';
 
-								window_init( &global_context->window3, (widget_t *)&global_context->desktop, 55, 5, vga->mode.x - 65, 100, VGA_COLOR_WHITE );
+								window_init( &global_context->window3, (widget_t *)&global_context->desktop, 55, 5, vga->mode.x - 65, 100, VGA_COLOR_CYAN );
 								((composite_widget_vtable_t *)global_context->desktop.vtable)->add_child( &global_context->desktop, (widget_t *)&global_context->window3 );
 
-//								text_widget_init( &global_context->widget3, (widget_t *)&global_context->window3, 1, 1, global_context->window3.base.base.w - 2, global_context->window3.base.base.h - 2, VGA_COLOR_RED, s );
+								text_widget_init( &global_context->widget3, (widget_t *)&global_context->window3, 1, 1, global_context->window3.base.base.w - 2, global_context->window3.base.base.h - 2, VGA_COLOR_RED, s );
 //								((composite_widget_vtable_t *)global_context->window3.vtable)->add_child( (composite_widget_t *)&global_context->window3, (widget_t *)&global_context->widget3 );
 
 								mouse_set_resolution( mouse, vga->mode.x, vga->mode.y );
 							}
+
+							// enable Z buffering
+							vga_use_z_buffer( &global_context->vga, true );
+
+							// draw on mode switch
+							((widget_vtable_t *)global_context->desktop.vtable)->draw( &global_context->desktop, &global_context->vga );
+
 							global_context->mode = MODE_GRAPHICS;
 							break;
 
@@ -325,6 +334,11 @@ static void handle_mouse_event( mouse_event_t *event, void *context )
 					break;
 			}
 
+			// alternative way of redrawing on mouse event
+			// on qemu looses the mouse..
+//			interrupts_disable( );
+//			((widget_vtable_t *)desktop->vtable)->draw( &global_context->desktop, &global_context->vga );
+//			interrupts_enable( );
 
 			break;
 	}