seg fault on second call to bgfx_frame

[chriscamacho]

okay I'm holding this wrong again!

I'm exploring the C99 API, here's my main loop, when bgfx_frame is called a second time it causes a seg fault...

    while(!glfwWindowShouldClose(window)) 
    {

		// Set view 0 default viewport.
		bgfx_set_view_rect(0, 0, 0, (uint16_t)WNDW_WIDTH, (uint16_t)WNDW_HEIGHT);

		// This dummy draw call is here to make sure that view 0 is cleared
		// if no other draw calls are submitted to view 0.
		bgfx_encoder_t* encoder = bgfx_encoder_begin(true);
		bgfx_encoder_touch(encoder, 0);
		bgfx_encoder_end(encoder);
        
        printf("*********** encoder touch *************\n");

        vec3_t at = {0.0f, 0.0f,  0.0f};
        vec3_t eye = {0.0f, 0.0f, -5.0f};
        vec3_t up = {0.0f, 1.0f, 0.0f};
        mat4_t view;

        //bx::mtxLookAt(view, eye, at);
        view = m4_look_at( eye, at, up );

        //float proj[16];
        //bx::mtxProj(proj, 60.0f, float(WNDW_WIDTH) / float(WNDW_HEIGHT), 0.1f, 100.0f, bgfx::getCaps()->homogeneousDepth);
        //bgfx::setViewTransform(0, view, proj);
        mat4_t proj;
        proj = m4_perspective(60.0f, (float)(WNDW_WIDTH) / (float)(WNDW_HEIGHT), 0.01f, 1000.f);
        
        bgfx_set_view_transform(0, &view, &proj);
        printf("*********** set view transform *************\n");


        //float mtx[16];
        //bx::mtxRotateXY(mtx, counter * 0.01f, counter * 0.0081f);
        //bgfx::setTransform(mtx);
        mat4_t mtx,mtx_x,mtx_y;
        mtx_y = m4_rotation_y(counter * 0.007f);
        mtx_x = m4_rotation_x(counter * 0.01f);
        mtx = m4_mul(mtx_y, mtx_x);
        bgfx_set_transform(&mtx, 1);
        
        printf("*********** set Transform *************\n");
        
        //bgfx::setVertexBuffer(0, vbh);
        bgfx_set_vertex_buffer(0, vbh, 0, 8);
        printf("*********** set vertex buffer *************\n");

        //bgfx::setIndexBuffer(ibh);
        bgfx_set_index_buffer(ibh, 0, 12);
        printf("*********** set index buffer *************\n");
    
        //bgfx::submit(0, program);
        //bgfx::frame();
        bgfx_submit(0, program, 0, BGFX_DISCARD_ALL);
        printf("*********** submit *************\n");
        bgfx_frame(false);
        printf("*********** frame *************\n");  // only gets this far once
        
        counter++;
        
        glfwPollEvents();
        if ( glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
        {
            glfwSetWindowShouldClose(window, true);
        }
    }

not sure I'm setting the buffers properly or what BGFX_DISCARD actually does...

[chriscamacho]

if it helps this is how I'm creating the buffers

    bgfx_vertex_layout_t pcvDecl;
    
    bgfx_vertex_layout_begin(&pcvDecl, BGFX_RENDERER_TYPE_VULKAN);
    bgfx_vertex_layout_add(&pcvDecl, BGFX_ATTRIB_POSITION, 3, BGFX_ATTRIB_TYPE_FLOAT, false, false);
    bgfx_vertex_layout_add(&pcvDecl, BGFX_ATTRIB_COLOR0, 4, BGFX_ATTRIB_TYPE_UINT8, true, true);
    bgfx_vertex_layout_end(&pcvDecl);
    //    .add(bgfx::Attrib::Position, 3, bgfx::AttribType::Float)
    //    .add(bgfx::Attrib::Color0, 4, bgfx::AttribType::Uint8, true)
    //.end();

    bgfx_vertex_buffer_handle_t vbh = bgfx_create_vertex_buffer((const bgfx_memory_t*)cubeVertices[0], &pcvDecl, BGFX_BUFFER_NONE);
    bgfx_index_buffer_handle_t ibh = bgfx_create_index_buffer((const bgfx_memory_t*)cubeTriList[0], BGFX_BUFFER_NONE);

[chriscamacho]

okay ! I see how I'm holding it wrong now!

will blog about it and post a link here later today...

[chriscamacho]

https://bedroomcoders.co.uk/using-bgfx-from-c/