PipelineStateHelpers.hpp

#pragma once
#include <isf.hpp>
 
#include <QtGui/private/qrhi_p.h>
 
#include <score_plugin_gfx_export.h>
 
#include <string_view>
 
namespace score::gfx
{
 
// --- String → Qt RHI enum mappers ----------------------------------------
//
// All mappers are case-insensitive and accept common synonyms
// (e.g. "lequal" / "less_equal" both map to CompareOp::LessOrEqual).
// Unknown strings fall back to a sensible default (documented per function).
 
SCORE_PLUGIN_GFX_EXPORT
QRhiGraphicsPipeline::CompareOp toCompareOp(std::string_view s) noexcept;
 
SCORE_PLUGIN_GFX_EXPORT
QRhiGraphicsPipeline::CullMode toCullMode(std::string_view s) noexcept;
 
SCORE_PLUGIN_GFX_EXPORT
QRhiGraphicsPipeline::FrontFace toFrontFace(std::string_view s) noexcept;
 
SCORE_PLUGIN_GFX_EXPORT
QRhiGraphicsPipeline::PolygonMode toPolygonMode(std::string_view s) noexcept;
 
SCORE_PLUGIN_GFX_EXPORT
QRhiGraphicsPipeline::BlendFactor toBlendFactor(std::string_view s) noexcept;
 
SCORE_PLUGIN_GFX_EXPORT
QRhiGraphicsPipeline::BlendOp toBlendOp(std::string_view s) noexcept;
 
SCORE_PLUGIN_GFX_EXPORT
QRhiGraphicsPipeline::StencilOp toStencilOp(std::string_view s) noexcept;
 
SCORE_PLUGIN_GFX_EXPORT
QRhiGraphicsPipeline::ColorMask toColorMask(std::string_view s) noexcept;
 
// Depth-attachment clear value to pair with a declared DEPTH_COMPARE.
//
// Depth after the viewport transform is in [0, 1], so a clear value only
// admits fragments on one side of it: 0.0 works with `greater` / `greater_equal`
// (the project-wide reverse-Z convention documented in CameraMath.hpp) and
// rejects every fragment under `less` / `less_equal`.
SCORE_PLUGIN_GFX_EXPORT
float depthClearForCompare(QRhiGraphicsPipeline::CompareOp compare) noexcept;
 
// The same, for a shader's declared state: uses its DEPTH_COMPARE when it set
// one, and otherwise the project-wide reverse-Z default.
//
// Every path that opens a pass with a depth attachment must go through this.
// Picking the clear independently of the compare is not a cosmetic mismatch --
// it silently discards the whole draw, because a clear of 0.0 admits nothing
// under `less`.
SCORE_PLUGIN_GFX_EXPORT
float depthClearForState(const isf::pipeline_state& state) noexcept;
 
// --- Conversion helpers ---------------------------------------------------
 
SCORE_PLUGIN_GFX_EXPORT
QRhiGraphicsPipeline::TargetBlend toTargetBlend(const isf::blend_attachment& b) noexcept;
 
SCORE_PLUGIN_GFX_EXPORT
QRhiGraphicsPipeline::StencilOpState toStencilOpState(const isf::stencil_op_state& s) noexcept;
 
// --- pipeline_state manipulation ------------------------------------------
 
// Merge two pipeline_states: every field that is set in `over` wins, otherwise
// `base`'s field is kept. Used to combine the descriptor's global state with a
// per-pass override_state.
SCORE_PLUGIN_GFX_EXPORT
isf::pipeline_state mergeState(isf::pipeline_state base, const isf::pipeline_state& over);
 
// Returns true if the state has any field set (i.e. would affect a pipeline).
SCORE_PLUGIN_GFX_EXPORT
bool stateAffectsPipeline(const isf::pipeline_state&) noexcept;
 
// Apply the state to a graphics pipeline.
// - `colorAttachmentCount`: used to size per-attachment blend vectors.
// - `depthAttachmentAvailable`: true when the target RT has a depth attachment;
//   depth-test/write are forced off otherwise.
// - `wantsDepthByDefault`: when state.depth_test is nullopt and this is false,
//   depth test/write are force-disabled; callers pass
//   `renderer.anyNodeRequiresDepth()`.
//
// Only fields explicitly set in `state` are overridden. Cull, front-face,
// polygon mode, blend, and stencil all preserve whatever the caller (or
// `mesh.preparePipeline()`) configured before this call. The caller is
// responsible for seeding sensible defaults (e.g. premul-alpha blend) before
// invoking this, so that shaders declaring partial pipeline_state don't
// silently lose unrelated defaults.
SCORE_PLUGIN_GFX_EXPORT
void applyPipelineState(
    QRhiGraphicsPipeline& pip,
    const isf::pipeline_state& state,
    int colorAttachmentCount,
    bool depthAttachmentAvailable,
    bool wantsDepthByDefault) noexcept;
 
}