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// Copyright (c) 2017 The vulkano developers
// Licensed under the Apache License, Version 2.0
// <LICENSE-APACHE or
// https://www.apache.org/licenses/LICENSE-2.0> or the MIT
// license <LICENSE-MIT or https://opensource.org/licenses/MIT>,
// at your option. All files in the project carrying such
// notice may not be copied, modified, or distributed except
// according to those terms.
use crate::command_buffer::synced::CommandBufferState;
use crate::pipeline::graphics::vertex_input::VertexInputRate;
use crate::pipeline::GraphicsPipeline;
use crate::DeviceSize;
use std::error;
use std::fmt;
pub(in super::super) fn check_vertex_buffers(
current_state: CommandBufferState,
pipeline: &GraphicsPipeline,
vertices: Option<(u32, u32)>,
instances: Option<(u32, u32)>,
) -> Result<(), CheckVertexBufferError> {
let vertex_input = pipeline.vertex_input_state();
let mut max_vertex_count: Option<u32> = None;
let mut max_instance_count: Option<u32> = None;
for (&binding_num, binding_desc) in &vertex_input.bindings {
let vertex_buffer = match current_state.vertex_buffer(binding_num) {
Some(x) => x,
None => return Err(CheckVertexBufferError::BufferNotBound { binding_num }),
};
let mut num_elements = (vertex_buffer.size() / binding_desc.stride as DeviceSize)
.try_into()
.unwrap_or(u32::MAX);
match binding_desc.input_rate {
VertexInputRate::Vertex => {
max_vertex_count = Some(if let Some(x) = max_vertex_count {
x.min(num_elements)
} else {
num_elements
});
}
VertexInputRate::Instance { divisor } => {
if divisor == 0 {
// A divisor of 0 means the same instance data is used for all instances,
// so we can draw any number of instances from a single element.
// The buffer must contain at least one element though.
if num_elements != 0 {
num_elements = u32::MAX;
}
} else {
// If divisor is 2, we use only half the amount of data from the source buffer,
// so the number of instances that can be drawn is twice as large.
num_elements = num_elements.saturating_mul(divisor);
}
max_instance_count = Some(if let Some(x) = max_instance_count {
x.min(num_elements)
} else {
num_elements
});
}
};
}
if let Some((first_vertex, vertex_count)) = vertices {
if let Some(max_vertex_count) = max_vertex_count {
if first_vertex + vertex_count > max_vertex_count {
return Err(CheckVertexBufferError::TooManyVertices {
vertex_count,
max_vertex_count,
});
}
}
}
if let Some((first_instance, instance_count)) = instances {
if let Some(max_instance_count) = max_instance_count {
if first_instance + instance_count > max_instance_count {
return Err(CheckVertexBufferError::TooManyInstances {
instance_count,
max_instance_count,
}
.into());
}
}
if pipeline.subpass().render_pass().views_used() != 0 {
let max_instance_index = pipeline
.device()
.physical_device()
.properties()
.max_multiview_instance_index
.unwrap_or(0);
// The condition is somewhat convoluted to avoid integer overflows.
let out_of_range = first_instance > max_instance_index
|| (instance_count > 0 && instance_count - 1 > max_instance_index - first_instance);
if out_of_range {
return Err(CheckVertexBufferError::TooManyInstances {
instance_count,
max_instance_count: max_instance_index + 1, // TODO: this can overflow
}
.into());
}
}
}
Ok(())
}
/// Error that can happen when checking whether the vertex buffers are valid.
#[derive(Debug, Copy, Clone)]
pub enum CheckVertexBufferError {
/// No buffer was bound to a binding slot needed by the pipeline.
BufferNotBound { binding_num: u32 },
/// The "vertex buffer" usage must be enabled on the buffer.
BufferMissingUsage {
/// Index of the buffer that is missing usage.
binding_num: u32,
},
/// A draw command requested too many vertices.
TooManyVertices {
/// The used amount of vertices.
vertex_count: u32,
/// The allowed amount of vertices.
max_vertex_count: u32,
},
/// A draw command requested too many instances.
///
/// When the `multiview` feature is used the maximum amount of instances may be reduced
/// because the implementation may use instancing internally to implement `multiview`.
TooManyInstances {
/// The used amount of instances.
instance_count: u32,
/// The allowed amount of instances.
max_instance_count: u32,
},
}
impl error::Error for CheckVertexBufferError {}
impl fmt::Display for CheckVertexBufferError {
#[inline]
fn fmt(&self, fmt: &mut fmt::Formatter) -> Result<(), fmt::Error> {
write!(
fmt,
"{}",
match *self {
CheckVertexBufferError::BufferNotBound { .. } => {
"no buffer was bound to a binding slot needed by the pipeline"
}
CheckVertexBufferError::BufferMissingUsage { .. } => {
"the vertex buffer usage is missing on a vertex buffer"
}
CheckVertexBufferError::TooManyVertices { .. } => {
"the draw command requested too many vertices"
}
CheckVertexBufferError::TooManyInstances { .. } => {
"the draw command requested too many instances"
}
}
)
}
}