vo_gpu: implement VO_DR_FLAG_HOST_CACHED

For OpenGL, this is based on simply comparing GL_VENDOR strings against
a list of allowed vendors.

Co-authored-by: Nicolas F. <ovdev@fratti.ch>
Co-authored-by: Niklas Haas <git@haasn.dev>

1 files changed, 16 insertions, 0 deletions

diff --git a/video/out/opengl/common.c b/video/out/opengl/common.c
index cf680e9c4c..ee2650867c 100644
--- a/video/out/opengl/common.c
+++ b/video/out/opengl/common.c
@@ -25,6 +25,7 @@
 #include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
+#include <strings.h>
 #include <stdbool.h>
 #include <math.h>
 #include <assert.h>
@@ -47,6 +48,18 @@ static bool is_software_gl(GL *gl)
            strcmp(renderer, "Apple Software Renderer") == 0;
 }
 
+// This guesses whether our DR path is fast or slow
+static bool is_fast_dr(GL *gl)
+{
+    const char *vendor = gl->GetString(GL_VENDOR);
+    if (!vendor)
+        return false;
+
+    return strcasecmp(vendor, "AMD") == 0 ||
+           strcasecmp(vendor, "NVIDIA Corporation") == 0 ||
+           strcasecmp(vendor, "ATI Technologies Inc.") == 0;    // AMD on Windows
+}
+
 static void GLAPIENTRY dummy_glBindFramebuffer(GLenum target, GLuint framebuffer)
 {
     assert(framebuffer == 0);
@@ -650,6 +663,9 @@ void mpgl_load_functions2(GL *gl, void *(*get_fn)(void *ctx, const char *n),
         mp_verbose(log, "Detected suspected software renderer.\n");
     }
 
+    if (!is_fast_dr(gl))
+        gl->mpgl_caps |= MPGL_CAP_SLOW_DR;
+
     // GL_ARB_compute_shader & GL_ARB_shader_image_load_store
     if (gl->DispatchCompute && gl->BindImageTexture)
         gl->mpgl_caps |= MPGL_CAP_COMPUTE_SHADER;